I have the MSR MiniWorks. I like it. It works well. You have to use it with a Nalgene bottle. The pumping can get tiresome (the dirtier the water, the more difficult the pumping is). Pumping from the muddy water of the Colorado River was the first time I used the pump and it took forever. I like to use a portable "kitchen sink" to bring the water to a nice spot where I can sit and then pump the water from my bucket of water.

I just purchased the "Platypus GRAVITYWORKS™ WATER FILTER".
Pros:
(1) I like to use a hydration bladder when hiking (instead of drinking from a Nalgene bottle). I find that I drink a lot more when I use a bladder. The "clean" bladder on this system will be my hydration bladder (I purchased an additional drinking hose to attach).
(2) This Platypus system is fast. I can fill it up and let it filter -- no pumping.
(3) I don't have to take apart my MSR filter and scrub the junk off of the ceramic filter.
(4) The Platypus system weighs 305 grams. The MSR MiniWorks weighs 414 grams + Nalgene (160grams x ?) + Hydration bladder (249 grams -- optional, but my preference to use a bladder). With the Platypus, the clean bladder holds up to 4L.

I'm very happy with my MSR MiniWorks system and I've had great experiences with the MSR customer support.
However, I'm going to try the Platypus system as a way to cut down on weight/stuff.

PinkRaven