I have the Sierra cup, it has served me well as a camping utensil, but at 6oz in weight, it's a little more than I want to carry as survival gear. It holds just the right amount of water for one of the "Mountian House" freeze dried meals, so that's a big plus not having to do a lot of measuring. I can boil water in it with my MSR Pocket Rocket in a couple of Minuets tops.

If I know I am going to be out overnight or for a few days, the Sierra cup is definetely with me. But for an afternoon hunt type thing, I'd rather loose some of the the bulk.