I've promised someone to tell them how the Premiere output looks compared to raw video.
I've taken those 2 zoo recordings that Ken made (monkey and antilop; M2TS, H.264, 60p, ~25Mbps, AC3, 5.1) and joined them in CS5, and exported them back out in MP4, H.264, 60p, ~14Mbps, AAC, 5.1. If you pay attention and/or watch on big screen, you'll see difference, but that's on sample that's way lower in bitrate. I think that you'd be hard pressed to see any difference if I left a 25Mbps bitrate for output.
So all in all, Premiere does a good job. I just think it's overkill for personal use, and way too expensive (again, for personal use). If you're into professional editing, than sure, go for it.. Premiere community alone is worth it. But for personal use.. I'm not so sure..
Btw, I'll have to install PowerDirector again, as I haven't tried exporting in 60p. 30p samples that I did are real good regarding picture quality, but a Indy car recording shows just how much 60p matters in fast movements..