From what I understand the discontinuation of Military MREs was twofold, to stop the resale of military stores by GIs looking to make a few extra bucks, and that the Military MREs are made with components supplied to the MRE manufacturers by the goverment and it was improper to sell meals with these goods back to the public with items already paid for by their taxes. I have eaten both types of meals, mil-spec and military, and the only difference seems to be that the mil-spec meals menus are limited and that the accesory packet, salt, pepper, toliet paper, tabasco, matches, spoon, and chicklets, are better in the military meal compared to the mil-spec meal. There are only two companies that make MREs and they also produce the mil-spec versions.
The Warnick Company
http://www.wornick.com/ and Sopackco
http://www.sopakco.com/
Another company, Oregon Freeze Dried
http://www.ofd.com/ the maker of Mountain House backpacking food also makes the artic rations and the Lrrp rations. Here is a good site to check out for current ration information and menus
http://www.dscp.dla.mil/subs/rations/rations.htm . An alternative to military rations is the Coyote Camp Meals supplied by the Supply Cache used by wildland firefighters.
http://www.firecache.com/ Click on online catalog then coyote camp meals. I've used all of the above meals, military and civillian, and they are pretty decent eating. They all are heavy and wouldn't want to pack them far but they're great for throwing into a truck or stocking a cabin. For woods walking I pretty much stick to instant oatmeal, instant soups, hot chocolate, and light weight items that use hot or cold water. Hope this helps.