Not entirely certain what you mean by 'perform'; are you referring to how the engines did in Russian winter, or are you asking more generally about how useful they were in combat?

Assuming the second, I will just note that, while the T34 and KV1 were probably the best tanks of their period, there are many occasions when there is a much bigger difference between no tanks and any tank whatsoever, than there is between a crappy tank and the best tank in the world. So at Moscow in December 1941, when the Kalinin, Western, and Southwestern Fronts had 670 tanks (!) between them (and only 205 of those were medium or heavy), the Soviets were undoubtedly very glad to have any Lend-Lease tanks at all, and might still have been glad to receive ancient Great-War-vintage Mark Vs. In fact the British had delivered 450 tanks by the end of 1941, which by then was rather a significant addition to Soviet tank strength - perhaps 100 of those 670 tanks before Moscow were of British make.

The British Matildas and Valentines were inferior to KV-1s and T-34s; but in December 1941 the Soviets did not have very many of those excellent tanks. Production hadn't yet ramped up from the disastrous losses of the 1941 campaign. Mass production of the two famous makes only really got underway in 1942. And the Matilda was certainly good enough to fight early-war German tanks. So, while it's hard to measure the exact impact - we can't rerun the Moscow fighting without Lend-Lease to see what happens - I think it's fair to say that the British tanks were an important addition in 1941, even if they became less so later on.

You can write a whole book on the subject (and Baryatinskiy did!), but here's a brief breakdown of how various vehicles performed.

Valentine

This was considered to be a good light tank. The 40 mm 2-pounder was considered equivalent to the domestic 45 mm gun in armour piercing performance (but a lack of HE shell was a detriment, more on that later). The armour was decently thick and high quality. The suspension was smooth enough to be able to fire accurately on the move, the engine was powerful and fuel economy was good.

There were also drawbacks to the Valentine. Canadian and British version of the tank came with different equipment, which introduced confusion during inventory. The turret was insufficiently protected from splash, the tracks performed poorly in the winter and could not grip the ground, track pins broke easily (this was later resolved by not tightening the tracks as much as British instructors wanted them to), and, most importantly, there was no HE shell. In addition to no HE, very few AP shells shipped with each Valentine. Soviet trials of the tank mention that you can use domestic 50 mm shells in the 2" smoke projectors and stick German MG rounds in British ammo belts, but the issue of cannon ammunition was a pressing one. The obvious solution was stick a 45 mm cannon into the tank. 2-pounders would be used in fortifications. Since many tanks came without machineguns (or sometimes any weapons at all) due to lax British control of the shipments, the domestic DT machinegun would be used as well.

A new gun mount was designed at factory #92 called F-95. The F-95 included a 45 mm gun and a DT machinegun. It also had an improved gun mantlet compared to the stock Valentine tank.

Even though a Valentine with this gun was built and passed trials, the program did not continue. The issue here was that 45 mm guns were desperately needed for domestic vehicles, plus it was unclear where enough manpower could be freed up to perform this rearmament. In addition, scathing letters sent from Moscow to London had their effect and the British improved their QA. Tanks started coming over equipped fully, carrying 520 rounds of ammunition per tank, and even with spare gun barrels. Other issues with delivery (broken engines on arrival due to expanding frozen water, broken batteries from freezing electrolyte, etc) were also resolved. It was decided that it would be easier to set up production of 40 mm solid shot domestically rather than produce more 45 mm guns.

Another attempt to equip the Valentine with an HE shell was made in 1942 when a shell from a Bofors 40 mm AA gun was combined with the 2-pdr casing and propellant. This idea made it to trials but did not reach production.

The Valentine IX with a 57 mm 2-pounder gun was found to be not much of an improvement. The tank still had no HE shell, but also no longer had a machinegun, making it completely useless against infantry. This time, the Soviets didn't just put in their equivalent gun (the 57 mm ZIS-2), but planned on going even bigger: 85 mm! It's unlikely that whoever proposed this project was aware of how much trouble the British had with putting the 17-pounder on the Valentine chassis, as the plan was to put the gun into a rotating turret. As you imagine, this idea never took off.

The poor protection of the turret from splash was also handled by Soviet repair crews. However, this was not done officially. Each unit improved the tank's armour in their own way, including 30 mm of applique armour in the front, a ring around the turret to prevent jamming, etc. An interesting idea by Engineer-Major Aleksandr Grigoryevich Aranovich was to weld on 45 mm armoured plates on top of the front of the turret platform and hull, but do so at an angle, giving the Valentine very impressive armour protection. Unfortunately this was not done on a major scale since GABTU (Main Automobile and Armour Directorate) did not want to increase the mass of the tank. This modification was implemented on at least three tanks in Aranovich's unit.

To solve the problem of tracks slipping, the Soviets added spurs to the Valentine's tracks. 8 spurs were added per track, with 12-13 links in between.

It is also possible that a few Valentines were converted into tractors (at least one, but likely more) during the war, and a few after.

Valentine tanks were continuously modernized by the British, and the USSR continued ordering them until the end of the war. Even Valentine III tanks with the 40 mm guns that were considered inadequate all the way back in 1941 were still around in 1945.

Doctor of Technical Sciences N.I. Gruzdev evaluated the Valentine as the best light tank of 1940-1943.

Matilda

Matildas were also subject to the same issues the Valentines were: the tanks were unsuitable for transport in cold conditions and service in winter (more so than the Valentines, as snow or mud packed into the suspension could immobilize the tank), inconsistent amounts of parts, supplies, and tools. These problems were solved in the same way as with the Valentine: harsh letters sent to the British and spurs welded onto the tracks.

Similar to the Valentine, there was a project to re-equip the Matilda with a Soviet gun. The gun the Soviets had in mind was not the 45 mm 20-K, but even better: the 76 mm ZIS-5, like in the KV. The resulting combination of a 76 mm gun and a DT machinegun for Matilda tanks was called F-96. However, like the F-95, the F-96 did not see widespread use. Mostly for the same reasons, but there was another one: the British started sending Matilda CS tanks armed with a 76 mm howitzer, which could do everything the Soviets wanted it to. Another problem was that the re-armament of the Matilda was initiated by the GAU (Main Artillery Directorate), but Matilda tanks were under command of the GABTU, and the two did not get along exceptionally well. GABTU had every reason to reject this proposal, as factory #112 would be tasked with performing the rearmament, and it was barely dealing with starting up T-34 production at the time.

One new problem with that Matilda was that the front tow hooks were weak and could be ripped off along with parts of the tank's side skirts during towing.

Unlike the Valentine, which was modernized throughout the war and kept up with the increasing demand on a light tank, the Matilda could not keep up. Orders for Matilda tanks ceased in the spring of 1943. By the end of 1944, you could only find Matildas in tank schools.

Tetrarch

Because of the small number of tanks sent to the USSR (only 20), the Tetrarch's role in Lend-Lease service is not well known. As you can tell by the number, the Red Army was not particularly thrilled with this tank. All 20 tanks were assigned to the 151st Tank Brigade, which also had 25 T-26 tanks. This brigade was relegated patrolling the border with Iran. These tanks also worked poorly during the winter (even in the relatively balmy Transcaucasian Front), the reliability was poor, the tank was found to be vulnerable to small arms fire, mortar shell fragements, Molotov cocktails, and even crowbars, and it was difficult to maintain.

The tanks eventually did get to fight the Germans in January of 1943, by which point Tetrarchs and T-26es weren't exactly top of the line models. By January 31st, the 151st brigade only had 14 functional tanks left. On February 26th, 1943, the brigade was pulled off the front and sent to reserves. At that point it had 14 Tetrarchs left (4 were non-functional). The functional tanks were sent to the failed landing at Novorossiysk, the broken ones were dug in to be used as pillboxes.

7 Tetrarchs were left by the end of May, transferred to the 132nd Independent Tank Regiment. By September, only 2 tanks still worked. 6 Tetrarchs were sent to repair factory #66 in Tbilisi, but all were written off because it was impossible to find parts for them.

The GABTU report that arrived in August of 1943 (more than a year after a tank was sent for evaluation) described the tank as complex, clumsy, and weakly armoured. It was considered useful only as an escort for cars in situations where they could be ambushed by submachinegunners.

Churchill

Three modifications of Churchill tanks were sent to the USSR: Churchills II, III, and IV, mostly III. Churchills were naturally considered heavy tanks and used in Guards Independent Heavy Tank Breakthrough Battalions, along KV tanks. The Churchill was plagued with many issues: poor suitability for winter or mountain combat (tracks slip when the tank tilts to 20 degrees), difficult to repair tracks, poor reliability, mudguards that bulged up when packed with mud and limited driver visibility and turret traverse, unreliable 57 mm gun. Firing the gun in certain positions could also tear off the mudguards.

However, the impressions weren't all negative. The performance of the 6-pounder was roughly equal to the Soviet 57 mm ZIS-2, the armour of the Churchill was thicker than on the KV, and equal average speed to the KV, despite a lower top speed. The favourite thing about the tank was the observation devices, based on the Gundlach periscope. This periscope was copied and went into production under the index MK-4.

Like the Valentine, Churchill tracks were given grousers to improve traction.

While the Churchill could be considered an equal of the KV-1, it paled in comparison to the IS-1 and IS-2, which eclipsed it in armour, firepower, and reliability. The last Churchills saw battle on the Eastern Front in September of 1944.

Followup question, were the controls on these re-labelled in Russian, or did the crews learn English? Were the measurements of distances, speeds, etc in metric or imperial?