LAST EDITED ON Jul-28-14 AT 12:29PM (MST)[p]Each filter has advantages and disadvantages. Gravity filters can be convenient around camp but I am not the biggest fan. I drink 4-5 quarts a day, so I need water more often than just in camp. While backpacking, if I spend a day hiking to and fishing multiple lakes, I am constantly moving and do not want to spend time waiting for a gravity system to work. Lakes are often above tree line and there is not a branch to hang it up on. I prefer a pump filter so when I need water it only takes 1-2 minutes to pump a quart. If I am hiking and come to a good stream crossing, I want to pump and go instead of sitting around waiting for the gravity system to work. This is just my opinion but they can be great at a base camp if that is the only place you need water AND there is water right next to camp. Often times I am camped at a lake that can be a water source but I still will pump the cleaner running water up the stream running into the lake or a nearby spring. In this case filling up the gravity system can be cumbersome with multiple trips (depending on your system?s volume) vs one trip pumping.
I have 3 pump filters, First Need Deluxe, MSR Miniworks, Katadyn Guide. (bought in this order)
The First Need Deluxe filters down to something like .02 microns (only .2 is need for bacteria) and is considered more a water purifier than a water filter. I'm not the biggest fan because it clogs up way to fast, even with back flushes.
The best feature for MSR Miniworks is that you can clean the ceramic filter insert over and over again. It works pretty good but the downsize is that the filter surface area is not the largest and it does require cleaning every couple days. It is just OK on speed.
The Katadyn Guide is my favorite. It pumps water really fast. Once I start pumping I can do a quart in about 15 seconds. The internal filter has been lasting a long time (multiple years). Someday I might have to finally replace the internal filter insert with the new one I have been carrying around for 5 years.
Just my 2 cents
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Edit: I have never looked into the Platypus gravityworks but if it is as fast as they say it is, it could be pretty cool.