Awesome So Far
I've tried a few reservoirs in the past - Osprey (punctured, didn't like the mouthpiece set up at all), CamelBak (I liked it, still have one for summer). For ski touring though, this insulated Platypus has been completely awesome. I've had it in around 0 degrees F and it worked like a charm. The mouthpiece freezes a little, but all you have to do is put it in your mouth for a minute and chew the mouthpiece and the water starts to flow. The tube is a little bulky to get through the little hole in my Black Diamond Covert pack to access the insulation strap from the reservoir storage slot, but I don't really ever remove it so I don't really care. Overall I have really liked it. I've seen a few negative comments about the cap, but I actually really like that too, and it works great on mine.