I've been using a First Need XLE pump for several years of Boundary Waters canoe trips. Double-acting pump and Nalgene-compatible is the way to go, and the taste is always great, even from sketchy sources. The advantage of a pump is water on demand, anytime. Also, it's always better to use water from away from shore. Also, in really dirty water you can always backflush with a pump.
A prefilter is definitely worth it--years of side-by-side testing has proven that. The prefilter from the Sweetwater system is great. MSR bought Sweetwater years ago, but now they've discontinued the whole line. I'll need to find something else when I run out of filters. The Sweetwater intake screen was great too. Coffee filters work OK, but are fussy. A dedicated screen/prefilter works better and is way easier.
I also have a Platypus Gravity Works. It's fast without the carbon filter, but does nothing for taste. The carbon filter is really slow and prone to clogging, but removes bad tastes (all taste, of course). The system is good and fairly lightweight for what it is, but my friend bought a heavier Lifestraw gravity filter, and it just works better, anytime we can justify the weight.
Platypus' dirty bags suck, the closure is terrible. The dry bag style (like Lifestraw and Katadyn's gravity systems use) is way better.