Price Paid: $150
I love this filter.
I have owned and own many other types, and backpack a lot.... I also travel in odd countries, and I always carry iodine and coffee filters as as pre-filter to extend the life of my filter.
For me, the fact that it was cheaper than the "hiker" yet offered better filtration (activated carbon, too) made it a no-brainer. The water tastes sweet and the pumping goes easy.
The pump body is hard molded plastic, unlike the 'hiker's metal, but I'm not worried about it at all.
The two caveats are that one should prevent it from freezing, or the ceramic will crack, (replacement ceramic only: 50 USD) and it is not an ultra-light pump for solo camping: But it will suffice for a larger party: We pumped for 12 using this filter alone. As a guide, it is my first choice to bring with me. At 30,000 gallons, it will keep pumping!
What a bonus, too, that you can use it in your RV or sink or wherever! I made a cool base-camp D.I.Y. sink from "instructables" (that's the url) with this filter as a flow-through - amazing! See the instructable titled "field sink".
Obviously this filter is a great choice for emergency preparedness, also B)
Price Paid: $160
Bought this filter in the spring and took it for a number of kayak/canoe trips over the summer. It was my first filter, but I'd had some experience using various other filters (belonging to friends) in the past.
I think the advantages and disadvantages of this filter were made obvious on one particular 5-day river trip, where my friend brought along his brand new MSR filter (waterworks?), and me my Combi. We'd often filter water at the same time in camp or on portages, and for the first few pumps the less expensive MSR filter seemed to match my Combi in both speed and water clarity (not that water clarity is necessarily proof positive of safe water).
In fact, I was even a bit jealous of my friend as the MSR's lever pumping action made it easier to grip than my Combi's piston action. This was compounded by the fact that the Combi didn't seem to grip the Nalgene bottles tightly enough and I ended up having to squeeze my bottle between my legs in order not to drop the whole assembly. (I later found out that the gripping piece that came with the filter was either broken or misshapen, and the replacement piece works perfectly.)
It wasn't until I was about a third of the way through filling a Nalgene that the Combi really hit its stride. I'm not sure how it worked exactly, but the Combi seemed to use built up pressure to dramatically increase filtering speed over the MSR filter, and after about twenty pumps or so, the Combi just took off and finished filling bottles in no time. It completely left the MSR filter in the dust and I was must have finished in a third the time it took my friend. The Combi seemed to use built-up pressure in the filter chamber to increase it's efficiency, and boy did it work.
I'm extremely happy with my Combi filter. Its speed and efficiency by far make up for its initial problems and difficulty of use. I'm not sure if anyone else has had the same Nalgene (or other bottle) gripping problems that I did, but if so I suggest you replace the gripping piece with a new one.