tl;dr: If you get it from the right manufacturer, they’re very okay, but a bit expensive, and don’t work for Shabbos unfortunately.
A MRE (meal ready-to-eat) is a type of ration primarily used for American military personnel and emergency relief workers, though some people also use them for emergency preparedness. They’re vacuum sealed in plastic bags and are designed to last for several years. They usually come with some way to heat them up without fire (e.g. a chemical pouch that heats up when water is added to it).
I’ve recently been interested in getting kosher MREs, but unfortunately there’s really only two major manufacturers in the United States. One of them is a kosher food manufacturer that happens to make MREs, and the other is an MRE manufacturer that happens to make kosher meals. The kosher food manufacturer’s MREs are….not good (I thought the meat was significantly past its shelf life). I have nothing good to say about them, so I’ll pass on naming them (because lashon hara).
The other manufacturer, XMRE, was more of a mix of good and bad. They send you 12 meals total, with 2 of each of 6 different main courses. All of the meals include:
something crunchy (e.g. corn nuts, dried chickpeas)
a main course (either pareve or fleshig; includes things like two bean chili, beef paprikash, pasta with marinara sauce, and chicken curry with lentils).
dried fruit (e.g. dried pineapples, peaches, etc.)
a bunch of tortillas
The crunchy snack always seemed weird and somewhat out of place with the rest of the meal to me. They didn’t have much flavor, and weren’t salted very much.
The dried fruit was really good! It’s by far the best part; I could have bought it from the grocery store yesterday.
The main courses are surprisingly not bad. They come in a pouch and you heat them up before eating. They’re obviously not as good as anything fresh, but I’d say they’re roughly on par with most canned food I’ve eaten, and they retained more flavor than I expected.
The tortillas are just ordinary flour tortillas. They’re bland, but I get they’re impression they’re supposed to be eaten with the main course.
The biggest downside: These really aren’t cheap. 12 meals for $185 works out to ~$15 a meal. You’re paying for the convenience.
The Vaad Hakashrut of Miami-Dade county’s hechscherr is on all the meals, and they’re on the CRC list so I assumed they were reliable.
They may not work for Shabbos lunch
I was curious to see if it was possible to heat up the MRE using my hot plate on Shabbos for days when I was too lazy to cook. Unfortunately, that doesn’t seem likely.
Of the various meals I got, only one of them (the pasta with marinara sauce) can really be considered solid (the marinara sauce was really thick like mashed potatoes). All of the other main courses are liquid or have significantly liquid components. Effectively, this means that you’re going to have to put them on the hot plate before Shabbos. Maybe you could eat them for dinner, but as for lunch the next day…I’m personally very uncomfortable leaving something on a hot plate for 15 hours (most of that unattended) unless it’s water or soup, which is why I don’t really eat thick liquids like curry for lunch on Shabbos. Maybe this is a personal hangup of mine, idk.
As far as how useful they are: it depends on whether you’re going to be somewhere without kosher food. For example, I had to go to a testing center to take a standardized test last week. This was in the middle of a major city without a kosher eatery around, and I took an MRE with me to eat before I took the test; it’s just a convenient way to eat a hot lunch if you go on an excursion to a place without kosher food (they don’t come with plates though, so might want to bring one or ask a nearby food-truck driver for an unused spare paper plate like I did).
They might be a good idea if you’re hiking or camping (although I don’t know; those aren’t things I do).