My understanding is that MREs do not hold up for a terribly long time. Freeze dried is supposed to have the longest shelf life (as compared to "dehydrated").
My own personal food collection is a mixture of everyday canned stuff that I rotate into the kitchen. Lots of canned vegetables, meat, soups, etc. Lots of pasta, rice, potato flakes, powdered milk, sugar, flour. I have been putting certain items into washed 2-liter bottles. Not a small amount of work goes into this activity. Most fun is collecting high end distilled liquors and wines...I figure that some day I will really enjoy consuming those. Or someone will.
But, yeah, I have quite a bit of freeze dried material on hand. Mostly in the canisters but lately I have taken to grabbing a few of the meals in envelopes that can be found in Walmart's sporting goods area. The problem is that all of that stuff is pricey. I find it hard to shell out several hundred bucks at a time for it.