We bought this to travel around India and Nepal with, it worked out on a longer trip more cost effective than using purification tablets, and we wanted to keep our usage of plastic bottles to a minimum, especially whilst trekking.
If you are taking this with you, then it's very sturdy, doesn't take up too much room and does what it says it does! (Our trekking guide in Nepal loved it and kept wanting to try it too!)
The only points i'd mention is that you need to make sure you have a water bottle with a wide enough neck to use this with (we didn't originally) and maybe take a spare battery - ours was fine until we reached the higher points on our trek where the battery warning light came on a few times - maybe the cold drained the battery too much? We kept in in our jacket pockets whilst trekking after this and didn't have any further trouble, but for peace of mind and if in cold environments we'd probably take a spare battery next time, despite this I was happy with the product and would recomend.