Well, I guess it depends on your definition of MRE (or MARE, meal almost ready to eat), but I've vacuum packed individual size servings of chili most recently. Also ham and beans turned out pretty good. Canned peaches and fruit cocktail are much cheaper to vacuum pack than buying them freeze dried.
I inherited my Foodsaver when my dad died, and I've used it a lot. Some of my friends get all obsessed with weight in their backpacks (cutting the handle off their toothbrush, for example), I don't so much. I figure, my own weight varies a few pounds without me noticing, I'm not going to notice an extra pound in the pack.
The vacuum packer really helps save space though, which for me is the more restrictive factor. In fact, I vacpack my spare socks, batteries, and other stuff just so everything fits well (and it's waterproof in case I fall in the river).
The longest I've kept the food portions before eating has been about a month with no refrigeration, they were fine. If you're thinking about long-term storage like a year or more, I'd stick to dry foods or freeze the portions.
But if you don't have a vacuum packer, I think you'll find it useful. The bags are kinda spendy, but can be rinsed out and reused, and cut down smaller. Hard sharp foods will poke holes in the bag and ruin the vacuum seal. Maybe one bag in 7 will lose it's suck after 24 hours or so, just eat that one first. It's not perfect technology (especially with an older machine like mine), but useful within it's limitations.
Parker