In WW2 which army had the best tasting rations? What about other luxuries like coffee and tobacco?

Oh my, one of my favorite category of knowledge during WW2, soldier culture. English is my second language so feel free to ask questions if I didn't make them clear enough.

Now, when talking about food. One of the biggest thing to consider is that how a food taste is a purely subjective thing. So which ever army had the best tasting one is a question that is impossible to answer. What I wanna do is to first get actual "chow" out of the way. Rations will come in the bottom half.

However, if we focused purely on what was provided and how the soldiers in general reacted to the food. It might provide you some insight.

Now, for the answer, I'm going to be biased here, early Imperial Japanese Navy had arguably the best food. (Early WW2, and I am counting China campaign here.) While not technically army liked you asked (I will go over that later), their marine (SNLF) division also got food that are quite nice by relative standards.

The navy, in the 1910s while building up the combined fleet under Fleet Plan 88 (Named after the planed building of 8 BBs and 8 CAs) wanted a food supply ship to be included. And that's how the Mamiya was borned.

The Mamiya had several facilities that makes it THE best food supply ship when it entered service. It had several large freezers and coolers for meat, fish, vegetables to supply 18,000 seamans for 3 weeks. It also included a butchering meat processing facility so if live stock can be found locally they can process them as well.

It also had a fully operational bakery that not only made your dry bread rations, but also all kinds of snack. Such as Monaka, manju. It also had a fully equiped ice cream making facility. On top of that they can make Ramune (Suger soda) using the ships boiler.

The ship also has a food processing facility on it. It is able to produce Konjac, Tofus, Aburage, Bran, and Yokan (!!) as long as it has the raw materials.

And of course, the ship employs a full capacity of professional cooks, from pastry chefs to sushi chefs, there is no lack of good cooks on the ship.

She does not have any armanant on the ship, so she was always assigned DD escorts. Reason being her sinking would be a large morale shock on the front lines.

Later on, the IJN also made another supply ship, the Irako. The Irako was basically the same, except it had a lower ability for food processing and also the ship was ran on coal to save oil for the combat ships.

Mamiya was unfortunately sank by the US Submarine Sea Lion on 12/20/1944.

The Irako was sank by the US carrier bombers while in Manila port on 09/24/1944 3months before the Mamiya sank.

On top of the 2 ridiculously amazing food supply ship. The ships themselves all had their own speciality food. From the Battleships to the Destroyers, especially their self-produced Ramune sodas that was made from the boilers. It is said that the Yamato had the best one out their (Of course, the account was from former Yamato shipmates so they maaaay be a bit biased).

Below is an example of a schedule of a ships food for a week from the biography of a ship cookhand "細井和喜蔵「女工哀史」" Also, please note all the dishes were served with white rice. The rice was served as all you can eat on most ships (Also the reason why the author of the biography volunteered, she came from a poor farm family)

Days	Breakfast	Lunch	Dinner
Monday	Takuan and Daikon Soup	Takuan and Fried Miso Pork	Takuan and Hijiki
Tuesday	Takuan and Turnip leaves soup	Takuan and and beans	Takuan and Tofu Pork Soup
Wednesday	Umeboshi and Ginger	Pacific Herring eggs and Takuan	Takuan and Daikon
Thursday	Takuan and Daikon Soup	Daikon and Takuan	Salt cooked salmon and takuan
Friday	Leaves soup and takuan	Takuan and Eddoe	Fukujinzuke (Pickles)
Saturday	Takuan and Umeboshi	Takuan and Tofu Soup	Takuan and Daikon
Sunday	Takuan and Tofu Soup	Ginger and Dried fish	Sengiri (A type of Mochi) and Takuan

(As you can see, they had takuan for literally everyday. The thing does match rice so...)

Then, you have the tradition of Friday Curry rice. I don't need to reiterate how amazing curry rice are. You can still get a taste of them at the JMSDF chow halls. They still retain the tradition, and the same taste. They are either called "Kaigun Curry" (Navy cury) or for PC purposes called the "Jietai Curry"(SDF Curry)

Now, for the marines, they were supplied by the Navy directly. And they get the benefit of getting the food supplies faster than the Army did.

And when they do go on an invasion or preparing for defense. Their ration consists of:

Kanpan - dried bread, it is still eaten today as a snack. It absorbed water VERY good, and it's ability to keep people full is well noted.
Kimpei candy - Suger candy. It literally, is a block of suger.
Rice - The most basic food in the IJA/IJN. When available it is taken locally. The japanese mess kit, while resembling the german one a lot, was designed to cook the rice in a really tasty manner due to the slight bend in the middle. I personally love to make it using it when I get the chance to.
Canned food - The staple of any armies. The IJA/IJN's canned food was consisted of preserved beef (everyone's favorite), and other assorted items ranging from fruits to preserved meat. According to soldiers, their favorite was either preserved orange or meal prepared from preserved beef. Japanese canned food was very heavy in taste, so a lot of soldiers loved it.

Sources:

聯合艦隊軍艦銘銘伝―全八六〇余隻の栄光と悲劇 by 片桐大自 (The Legend of the Ships of the Combined Fleet, the glory and tragedy of all 860 and some ships)
女工哀史 - 細井和喜蔵 (The sad story of a women worker)