Some have said the 3fps is fine. Heck, 1 or 2 fps is fine if you don't do a lot of action or birding (specifically BIF). All I know is that when I borrowed a 1DMkII, I got a higher keeper rate BECAUSE of the faster
AF and FPS. At one time, I was specifically looking for a used one with a couple of long teles to do this kind of photography. Then I heard about the K20D and I hoped that it would have a higher fps. So much for that.
The K20D is not comparable to the
af and framerate performance of the 1DMkII. If anything, it's more like the 1DsMKII, a studio, landscape, and single shot beast (if the
IQ holds up). I will probably get it just for those purposes, but I will still be hunting for a sport and BIF rig...