So I've had CS5 forever, but mostly only used AE and PS, and FCP7 for video duties. I just now started playing with PR to see how it works in anticipation of a future wholesale switch to CS6.

With the included FCP keyboard template setup, the actual editing part seems good enough... does most things that I've asked it to do and plays back mixed media quite smoothly.

HOWEVER...

At first glance, exporting sucks. I have not been able to export a single thing with sound. No setting that I ever plan on using will send audio readable by any program whatsoever. Even video playback of "vimeo HD" and "YouTube HD" h.264 in any program (QT, VLC, MPX) is choppy and pixelated (and silent). It will only output ProRes in SD resolutions, and I can't seem to override that. Even attempting to output in sequence-native format just gives a nondescript "error in compiling..."

Is there a software incompatibility here, or some magical concoction of file settings to which I must adhere to hear anything?

It definitely sounds like there is some problem. I would suggest trying to reinstall the suite, perhaps some codecs got overwritten afterwards.