I switched to the 60fps mode and shot a minute of video of my wife and cat. When I played it back, it was just as smooth as when I shot it, with no hiccup or stutter or anything that might be indicative of a transfer speed problem. I played it through at slow motion speed as well, and didn't notice any problem.
In my mind, it seems like the highest transfer rate would be at the 30 fps/ 640x480 setting, since that would be capturing four times as many pixels per frame as the 60 fps/320x240 setting. Sure, it's half as many frames per second, but still twice the raw data. Either way, I shot some footage in the 30fps/640x480 mode, and about 22 seconds into it started getting the red exclamation mark that means it's running out of internal memory buffer (because it's not able to flush out to the SD card fast enough). After about 42 seconds, the internal memory filled up, and it stopped recording. Hmph.
I looked at that Pentax as well, but the things that kept me from getting it were a slightly slower startup time and a non-standard USB port (one more cable to lug around) (I haven't verified that this particular one has a non-standard port. I just remember what the other Pentaxen I looked at had.) Additional factors were the bigger viewfinder on the Canon, and generally liking the Canon's look and interface better. I did like the idea of the docking station for the Pentax, but as far as I can tell, it's just for charging and not for USB. I didn't even remotely consider image quality between the two, however.
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-Aaron