I've been using the MSR AutoFlow for awhile now and have been quite impressed. The fact that it weighs in around 10 oz, filters at about 2L per minute, can be effectively cleaned by reversing the flow, and is the easiest filtering solution I've ever used making it my go-to backcountry filtering solution. I've used it numerous times on the Colorado River and have not had any problems with clogging.

Having said that, it isn't the best solution for humic acid (ie., Boundary Waters) or blue-green algae prone areas (ie., High Uintahs). If these exist in the areas you frequent then a hollow fiber based filter might not be the best choice. I would go with a filter that uses a ceramic cartridge (I don't think there is a ceramic gravity filter available but I could be wrong).

The best part about the filter is that I have instant water without work. It's awesome! Check it out here.