I would recommend a Steripen with, say, Micropur tablets as backup. I have used a Steripen Adventurer now for almost four years and have had good service with it. At first, I had problems with it; they require quality batteries and I hadn't read the instructions as well as I should have. But now, with a clean water source, I can have a drink inside two minutes. The Steripen also works well on protozoa, bacteria and virus. Filters won't get viruses and chemicals are not reliable on protozoa cysts.
The Steripen does require that the water be clear to work; the UV is quickly attenuated by murk. I don't use my Steripen here in Arizona where a lot of the water sources are murky to say the least. For most hikes in AZ I use a pre-filter (a coffee filter or bandanna) then a pumped or gravity filter and then chemicals. Even then, a lot of the water smells like reclaimed waste water. But, I have never gotten sick from it.