If the trip has access to clear stream water I prefer the Steripen. Lightweight and fast. If you expect occasional debris then just pre-filter with a bandana. If you expect a bit of off-putting flavors then I bring a water bottle with an activated charcoal filter (Steripen in the bottle, then put the cap on and drink through the AC filter).

For larger groups, where sterilizing a liter at a time gets annoying I have a BeFree filter with a reservoir. I'm not sure I would recommend it though. I've read an awful lot of failure reports of the thing getting clogged and last I checked they do not have an appropriate integrity check.

Some years back I did a trip in the desert during rainy season. Water was available but very muddy. It was nice to have a filter that was easy to clean. I think we had an MSR Miniworks. Pump until the filter clogged. Open it up and pop out the filter, clean it off, put everything back together, and keep filtering.

The one thing I bring along with me is the piece of mind that backcountry water (at least in the US/Canada) isn't really that full of nasties. They did a survey of people coming off the AT. No correlation was found between water treatment technique (including people who did not treat at all) and getting sick. A strong positive correlation was found with cleanliness habits. I treat all my water because, even if the chances are low, I don't want giardia or the ilk, but I spent more time worrying about if I washed my hands well enough after I went to the bathroom.