Personally, I drop the XDCAM EX files into a ProRes timeline then edit, render and export. You can get Compressor to convert the files before you start editing if you wish. Compressor is faster than doing the same thing in a timeline in FCP but then you have to convert all the files, instead of converting just what you need at the end of the edit.
Converting in Compressor gives you more control over the cross/down conversion process if you have to do things like de-interlace or go to a smaller frame size, but all things being equal, you won't see much of a quality difference under normal circumstances. What flavour of ProRes you use will depend on what the end product is for and how much manipulation you have to do to the media.
- Don
Don Greening
A Vancouver Video Production Company
Reeltime Videoworks
http://www.reeltimevideoworks.com
