Big fan of the MSR Hyperflow. The ability to back-flush is a big help with silty rivers. A filter that had been in use for over a year filtering clearish water got my wife and I through 5 days on Labyrinth/Stillwater being only moderately careful about setting before filtering. I brought an extra cartridge but never swapped it out. Back-flushed every couple liters, and though resistance was a up a little, still pumped fine when we took out.
Small, simple and light. Frequently carry it in a jersey pocket for long bike rides.