This is probably the best selling big wall hammer ever. It has a time-tested design that has gotten people up big walls from Yosemite to Baffin. It is the perfect hammer for light nailing routes and climbs where you won't be nailing your brains out (which is 99 percent of most big wall ascents).
This is a good solid hammer for your average Yosemite climber. If you are a big wall addict, I would try to find an A5 hammer or similar model with the ability to place copperheads and a little more heft. But for most climbers this will get the job done. The only other hammer I have used recently is the Petzl Bongo Hammer. I was pretty impressed with it but I did not get to test its copperhead placing abilities.