I had used a Sawyer Gravity feed system for several years with excellent results. Although I used it mostly for solo adventures, it is perfect for a couple people to use at a base camp. A few summers ago my brother and I hiked the 48 miles across Isle Royale, using it as our only water filter. It was an extremely fast, 1 person operation that made it easy for 1 of us to cook while the other handled the water and limited the amount of time we had to stop hiking.
I really like being able to let the water filter while doing other things around camp or just stopping for lunch. I've found that if water is easier to filter, you'll use more and stay better hydrated. Last year in our 2 man spike camp, we just kept filling up the "dirty" bladder after every batch and always had it waiting to filter as soon as our clean bladder was used up. One down side I found last year was that the filter can freeze up overnight, so if the temperature is going to drop flush the system out before heading to bed.
Although I was a fan of the Sawyer, i just switched to the Playtapus system and it is WAY better. 5 ounces lighter than the sawyer (2L option), and that is with the pouch, all filter accessories, and both 2L bladders....which you probably won't need. The filter itself is extremely light, and you can customize your options to filter directly into any of the Platypus bladders or bottles with the accessories provided in the kit.
I have my filter kit set up with the 2L dirty bladder, filter, and softbottle attachement. I leave included 2L soft bladder at home, and just filter directly into my 3L hoser bladder, and then also pack a 1L softbottle for mixing energy drink. All together, this system saved me about 8 ounces off my Sawyer setup and it packs much smaller.
I also still pack the Vapur 1L filter/bottle at times. At 2.3 ounces, it is perfect when you know you'll have access to water throughout the day and don't need to filter/pack a lot of water to get you through the day. In a pinch it can also be used as a squeeze type filter if needed, but it is slow and kind of a pain in the ass to do a lot of water at once.