Unlike FCP, Premiere Pro will natively handle the files as-is without any kind of transcoding.
This means there is no loss in quality when you are editing. As long as you export to a medium that is the same or higher quality you should see no loss in quality. Keep in mind that DVCProHD can have generational loss around 10+ exports.
Depending on what you convert your DVCProHD files to in FCP, that will determine if there is a quality loss. ProRes 4:2:2 should yield no quality loss, but will yield a generational loss after so many re-encodes.
After you transfer to DVD, Blu-Ray, or Streaming media there is quality loss since those are all 4:2:0 mediums and there will be a quality loss even if your bitrate is infinitely high.