Boiling is great for food(freeze dried, ramens, etc), but for drinking water its a huge fuel/time waster in a survival situation. Plus, who wants to wait around for the water to cool while out on a hike. And tabs..? No chem taste(tabs) either or waiting for them to take effect(30 minutes?..a good filter will pump a liter in 60 seconds flat. Bam. ..nice clean water). Plus for either, you have to first dip your water out from somewhere deep enough to allow so. Up high in the mtns, many many times theres only a small tiny water source to pull water from. Most filters use a small "acorn" that can be dropped into a small seeping hole the size of a 1" deep ashtray.
As far as lasting, my PUR Hikers element lasted a couple of years of backpacking 30ish times a year back when I backpacked alot, before I felt the need to replace it(of course this depends on how dirty the water is on average that one is pumping). Even then, it first just gets harder and harder to pump over the course of months.