I have three different models and have retrofitted insulated drinking hoses to the ones that didn`t originally have them. One model is bicycle/ski specific in that there is no facility for storage - just an insulated shell designed to store a bladder that will handle a couple liters of liquid.

Skiing I wear one under a ski jacket. Bicycling I use one to supplement a couple water bottles. The previous poster has decided sweating was an issue. I guess thats a personal observation based on how he was using the Camelback. Skiing, perspiration is a general occurance and results in loss of body fluids. Same for bicycling except that do to the nature of the sport, its possible that perspiration can be trapped under the Camelback and be more noticable. In the real world thats only an issue in extremely hot and humid conditions.

But there is a strategy that pretty much solves the whole `sticky` situation. If the Camelback is left in the freezer overnight so that the contents are frozen, it will be 4 to 6 hours before they will gradually become liquid. In the meantime the insulation will limit temperature transfer and keep your back cool but not cold. That works best for me because I`ll go through 2 water bottles before the Camelback contents start to melt enough to provide a liquid source.

I imagine that if the Camelback was your primary drinking source and not your secondary, then a couple hours in the freezer would probably be enough.

The only downside to these is that they do require maintenaince. They will mildew if not washed and dried on a daily basis. But then - so will any regular waterbottle. Its usually the silicone ring under the cap on a stainless or plastic bottle that starts to have issues. With a Camelback - the whole bladder plus the drinking hose needs to be cleaned..

Again - a lazy way to deal with the situation is to store the bladder and hose in the freezer when not in use. Personally I`ll take a Camelback over a waterbottle any day - mostly because a waterbottle just dosen`t hold enough. But then there are convenience stores everywhere in most cities and Gatoraide, bottled water and fruit juices are pretty easy to come by too.