I've been using the Sawyer Squeeze filter for all 5 of my trips in the last 5 months. So far, I've been pleased with its performance, ease of use and adaptability. It's a simple, lightweight water filtration system.
Early on I swapped out the factory supplied squeeze bags with an old 2L platypus. Haven't had any trouble with a leaky seal which differs from some other reports earlier in the thread.
On the clean end of the filter, I've mostly stuck with using the factory supplied push/pull cap but have also, on one trip, instead used a modified tornado tube to connect the clean end of the filter to another 2L platypus. This worked great as well and I couldn't see any evidence of leaks from a bad seal.
Most of the time I've used the filter in squeeze mode or an inline mode, but with the tornado tube and clean 2L platy, I set it up in gravity mode: 2L dirty platy hanging from a tree> squeeze filter > tornado tube > 2L clean platy. Without any user input, the squeeze filter appeared to filter at a comparable rate to the standard 3-way Sawyer filter (about 2.5- 3 mins/liter). A nice option for camp while going about other duties.
For a water scoop, I cut down an old platy. Makes it easy to get water out of the creek and pour into the dirty platy. Adds all of an ounce, if that, to my water filtration system. I wrap my dirty platy and water scoop up around the filter and rubber band it together. I leave the protective cap on the push/pull cap on the clean end to protect it from contamination when not in use.
Out of the 5 short trips I've used it on, I've only backflushed and cleaned it with a bleach solution once, although I always rinse and shake it out real good and do my best to dry it out before storing it away. Haven't noticed any changes in performance yet. I don't have to contend with freezing temps for long term storage, but when camping I try to shake out any water and then stuff it in whatever is handy (ziploc, stuff sack, etc.) and throw it in the bottom of my quilt.
All in all, I find the Sawyer Sqeeze to be an improvement over my most recent past methods of water treatment (which was the 3 in 1 Sawyer filter used in a gravity set-up), primarily due to the savings in weight, flexibilty of ways to use it and simplification of set-up. I've played around with a Steri-Pen Adventurer Opti as well in the last year or so, and it too was easy to use, but I'm finding the Squeeze filter is just a better fit for me. I like knowing the water is passing through a filter as opposed to zapping it with a UV lamp that may, or may not, be working properly. Plus the Sawyer Sqeeze benefits from no batteries to contend with, about the same size/weight as the SteriPen and it's better for filtering larger amounts of water (1.5 L+) at one time. I think I've found my winner.