I have a Camelbak UV bottle. Finally used it recently on river water. Was great:
UV pros (mine & Steripen):
Takes about 60 seconds, not up to 2hrs
Also kills viruses*
Quick and easy
Camelbak comes with a 750ml bottle & spare plain cap
Use as drink bottle & hot water bottle
Is rechargeable
60 cycles of 750ml
Does not upset natural gut flora!
Cons:
Can get broken
Does not treat bottle threads
Not as light as chemicals
(always carry a secondary purification method in your First Aid kit)
Compare the weight and treatment features with pump filter and drip systems. Glad I kept this one now. Only paid $125, think it was forgotten on the shelf

I also have their additional pre-filter cap, unused to date.
* UV light disrupts the DNA of the bugs so they can't multiply in your stomach, they may however reconfigure if left in the light for a few days.