I transcode all of my 7D footage to ProRes before editing. After that point I treat the project like anything else I edit in FCP. I've exported to SD DVD and also to 720p H.264 for the web, using Compressor. I usually make sure the Frame Controls are active and the Resize Filter is set to Better(Linear Filter). This seems to offer great quality scaling without the extra processing of the Best(Statistical Prediction) filter.
I tried a couple of 720p exports using compressor, but it took in excess of three hours! to export an 8 minute video.
I must admit i've never really used compressor before, is it usually this slow.
I've done a couple of tests this afternoon, exporting as a final cut ProRes 720 quicktime, then compressing to h264 in streamclip it's it's nigh on impossible to tell the difference between the compressor version and the streamclip version.
Yikes! That is a long render. That definitely hasn't been my experience. MPEG Streamclip is one of the coolest programs I've ever used, and it's free. I use it a lot, but typically I use Compressor for most project.
Have you tried sending the same clip through Compressor? I've noticed if I send a sequence to Compressor straight from Final Cut, it takes longer than exporting a Quicktime from Final Cut first, then using Compressor to transcode the clip. It's a two step process, but so is sending the clip to MPEG Streamclip.
Of course, if MPEG Streamclip does the job for you, I wouldn't deter you from it. It has some awesome features and uses the same Quicktime codecs that Compressor uses.