Performance, while not identical to the S2's, is either the equivalent or better. Start-up to first shot takes only 1.5 seconds, which is quite zippy overall, and extremely good for a camera that has a long lens to extend. Shutter lag in bright light runs about 0.4 second and doubles to 0.8 second when the lights get low. The S3 is also relatively responsive: 1.1 seconds typically from shot to shot, plus another second if the flash needs to recycle. Though it maxes out at 1.5fps in continuous-shooting mode, there's no buffer-constraint on the number of sequential shots at maximum resolution; I find that much more useful than a fast but limited burst mode. It was certainly sufficient to capture active dogs and children playing in the park, including kids spinning in a tire swing.
Autofocus occurs quickly for the most part, although a few of my shots looked as if the focus hadn't locked before capture. I didn't experience any of the problems that the S2's reviewer did with SuperMacro mode; it worked fine for me, even with the lens almost pressed against the subject. The image stabilization bought me about two stops of shutter latitude, but my hands shake like an octogenarian's--a coffee-drinking octogenarian.
I'm not a big fan of electronic viewfinders (EVFs), and the S3's didn't convince me otherwise; though it's fine for framing, I hate that it freezes when the shutter is pressed. The LCD is certainly viewable in most light, but I prefer an eye-level viewfinder to the unsteady arm's-length approach.