IMO, the biggest downfall of the Sawyer system is how difficult it can be to fill the bladder if you don't have access to a lake or free flowing stream. Especially above treeline where you're getting water from seeps or trickles from a rock glacier - this can be hugely annoying. For me, I use the Sawyer system in summer and early season when I know there is an abundance of water but I always take the Katadyn Hiker Pro when I'm less certain of water availability. Its a significant weight penalty but its worth knowing I can use to to pull water from almost anything.