Good for some things
Used the six liter tank every day for a month getting water for camp on the AT. Due to the lip-lock top, I would never put this into my pack. Originally purchased the tank due to worries about far water sources. By filling this at camp once in the evening, my boyfriend and I were able to re-hydrate, make dinner, brush teeth, and take 2-3 liters out of camp in the morning.
Filtering water out of this tank was much easier than filtering out of the 10L sink we carried before, and there was no plasticy sink taste.
Filling the tank was sometimes a challenge at springs. If the spring was not piped out (or the pipe was low) we would have to try to let the tank fill through the spout, moving rocks to make the stream deep enough to fill the big tank. Often I would simply resort to scooping the last couple liters of water into the tank by hand, since we filtered it anyway.
Walking back to camp (up to .3 miles and up to 350 vertical feet) was often enough to make the bag pop open, but VERY careful and thorough sealing made this happen much less frequently. All in all, I was happy to have this, it just needs to be used within its natural limits.