I use a Sawyer Squeeze water filter with 2 x 2L CNOC bags. 1 bag to collect "dirty" water, and the other bag for the clean filtered water. I bought the coupler for the filter which allows you to connect both bags and create the best/lightest gravity system I have seen. The CNOC bags roll up and weigh virtually nothing. I couldn't find a great picture of it in action, but you can zoom into these photos and get an idea. 

Photo 1 shows the clean CNOC bag removed from the filter. Photos 2 and 3 show the system in use.






 

Solo I use a Platypus Quickdraw filter and 3L CNOC bag. Weighs 6 ozs or 10ozs less than a mini works. It’s fast and I have never had a clog. (used the befree before this and moved over because of clogging) 

Don’t think you could go wrong with a Sawyer filter either like the Sawyer Squeeze.  Been around forever. People swear by them.