You can never have too many options for treating your drinking water while in the mountains. I use Iodine, Chlorine Dioxide (Aquamira), Water filters like Katadyn or LifeStraws and have even used a Steripen.
Each have their Pro's and Con's but I find Iodine tabs to taste the worst but be the most compact and easy to use. A very small set of sealed Iodine tabs live in my pack always. Aquamira is my "Go To" choice for lightweight packability and use and comes on every trip. They last for years and treat HUGE amounts of water. Some people say there is a taste, but I think they make some great water out on the trail. They even kill Cryptosporidium after 4hrs. Combine this liquid treatment with a large lightweight bladder and you've got all the treated water you could need and never have to pack a heavy filter again.
Filters are nice if your water sources are disgusting and limited but pack size and weight plus filter life make them higher maintenance over time. Filters clog, tubes break, pieces get lost, etc. Nice to have but I use filters for specific trips to places where Cryptosporidium is highly present or when I'm pulling my only water from some smelly mud puddle filled with junk. Aquamira for the win :)
CHOKING HAZARD -- Small parts. Not for children under 3 yrs.