British ration packs are pretty good these days. They include soup and like 50 different kinds of drink sachets (drink some tea! drink some coffee! drink some hot chocolate! drink this soup! drink five kinds of sports drinks and 12 different cordials, there must be something here that takes away the taste of jerry can, just fucking drink you fucking fucks) per 24hr period to help with hydration and constipation. The meals are much better than you would expect, my favourites were beef with cassava, lamb casserole, leek and potato soup and a fairly decent chilli, though I've never eaten anything that was really bad. Snacks are good, I like the roasted almonds, the squidgy fruit packs and the chocolate-hazelnut spread. The hot chocolate is really good for instant as well, better than any store brand I've ever had anyway.
Having said that, they're expensive to buy, they only taste good for what they are, and they're not really something you'd want to eat long term. There's not much fibre in them, they're high calorie, there's no dairy and very little fruit/vegetable content, though I assume at least some of it must be fortified. It's convenient food that gives you enough energy to function in the field and throws some sweets at you to keep your morale up, but it's not meant to be a long term diet.