Hydrapak is the best, imho, but other brands have upped their game a little in the last couple years. They started out with Dakine and Geigerrig, always been the same high quality material. Never had a leak or a burst out of the four I own & use...did have to get one replaced after I abused it with too much bleach (better to use non-bleach sterilizing tabs or other methods). The brand new 2017 MSR Dromlite bags are worth a look too if your needs are more for storage or gravity filtering rather than a straight up drinking bladder. Much prefer these slide-zip closures instead of screw lids. Easy, quick, and effective.