I have been dabbling with the Trekmate version of these so do not,available from REI, http://www.rei.com/product/849340/trekmates-flameless-cook-box-kit.

I find them to be useful, but rather expensive; over a dollar a meal seems excessive. The heating units are simple to use, but be aware that the most common chemistry generates hydrogen - be careful in confined spaces. You most commonly merely heat boil in the bag items. I have been able to do my standard oatmeal and fruit mixture quite well. I also did a very nice scrambled egg with the larger pack and it was great.

I want to see if the Trekmate bo will play nicely with the standard MRE heaters; my guess is that they will. That might help the cost a bit.

I am glad I got my unit (yes, I would recommend them to a friend). Just right for those situations where a live flame is a no-no.