After searching for hours and hours multiple times I've decided to post here.
I've exported from FCP multiple times with different settings, whether it be H.264 or PNG or uncompressed I always feel my end result is worse quality than my original .mov file.
I usually transcode to Apple Prores 422 HQ, edit in FCP, then export but I always get the same result. Regardless of the file size of my export (from 100mb to 40GB today) the video is worse quality than my original files.
I did notice when I exported in Uncompressed 10bit the quality is much better, although my video is squeezed into a square.
I'm shooting with a 7D at 24p.