I'm a medium distance runner and have tried several hydration systems over the past year.
Carrying bottles on a belt, which weas not enough in the summer.
Other bladders which warm up from body heat and produce plastic tasting water. (Despite BPA free DHA free blahblah free etc.)
I have been on 6-hour walks with this on the back, the water always tastes clean.
So convenient having the bladder built into the bag, no need to fill it up and slot it's in.
Also makes puncturing the bladder very difficult.
Before each use I swill it swill the bag and spit out the first few mouth fulls of water to ensure the pipe is clean.
Requires no more washing than that.
I am going to buy another just in case they are not available when this one is finished (probably in 10 years' time lol)
If only it had a zipped pocket for keys and phone, it would be perfect. There is a small pocket in the back, but it's probably only suitable for a map, or a slim phone without a case.