Allow me to post a brief overview of Manstein's campaigns, they don't do them justice but detailing his entire campaigns really deserve their own post.

"Sickle Stroke"- arguably his most famous work, and possibly his greatest contribution to the German war effort. His revised plan for the invasion of France called for the armored thrust into the Ardennes that was responsible for defeating the French so quickly.

Next Manstein was transferred to a panzer crops at the start of Barbarossa, Manstein's corps fought very well and Manstein earned distinction, but he had a habit of outrunning his supply lines and almost got his panzer corps destroyed when he got encircled by the Soviet 11th army.

After this Manstein was transferred to the German 11th army under army group south in the Ukraine. His goal was to capture the Crimea and take Sevastopol. Manstein slowly worked his way into the peninsula but due to lack of manpower his assaults on the fortified city failed. He was able to stop a Soviet counterattack from taking the eastern part of the peninsula though. Manstein eventually got the air superiority and support he needed. He took both Sevastopol and another city on the peninsula called Kerch. Hitler promoted Manstein to Generalfeldmarschall because of his victory.

He was than transferred to the city of Leningrad, where he made the decision to starve the city by cutting of the supply route across lake Ladoga. However, the Soviets launched the Sinyavin Offensive, and while Manstein was able to repel the assault, the Germans were too weakened to launch a final assault on the city and they had to commit to a siege.

Manstein was now given the task of reliving German troops in Stalingrad (operation Winter Storm). Manstein's "Army Group" consisted of the trapped 6th Army, a smashed Romanian Army, and the 4th Panzer Army (which had also suffered losses), in spite of this Manstein almost managed to free the 6th Army but Paulus was unable to attack the Soviets in the rear and Manstein had to call of the assault

The defeat at Stalingrad opened the floodgates and the Soviets pushed back hard. Manstein launched a counter offensive that was extremely successful destroying three Soviet armies and preventing the collapse of the entire front. He even recaptured the city of Kharkov.

Manstein's first real defeat would come at Kursk. Manstein;s offensive was successful at the start but the Soviets began to turn the tide. The offensive was finally called of by Hitler who had to focus his attention elsewhere (the allies had landed in Sicily). This infuriated Manstein who thought that one more push would break the Soviets at Kursk. In reality Kursk had failed and there was no hope of victory.

Now the front began to collapse and the Germans began to lose territory rapidly. The Germans just didn't have enough men to cover the front and Manstein's counter attacks could do very little to hold the Red Army juggernaut back. This continued until Manstein was dismissed in March of 1944.

I do think Manstein had his reputation inflated by the Western allies who admired and respected Manstein but he was certainly a brilliant general in his own right. Its hard to quantify him as the greatest general, if only because everyone has a different opinion on what makes a great general. Manstein's sickle stroke was probably his greatest contribution to the German war effort and arguably his greatest feat; its probably also one of the most daring and brilliant moves in war history. His campaign in the Crimea was nothing short of brilliant. Finally, his ability to keep the Red Army in check after the German collapses at Stalingrad and Kursk all speak to his abilities. Was he the greatest? Probably not. But he was certainly a great solider and a great general worthy of distinction.

A good book on this matter is:

Manstein: Hitler's Greatest General by Mungo Melvin.