Videomaker – Learn video production and editing, camera reviews › Forums › Technique › Editing › AVCHD to MPEG2 › Thanks Dan.
You can pick any codec apart and find articles that support theories of issues with any of them, like color shifting with ProRes or X issue with Cineform or DNxHD. But like I said you will find the happy medium when you find what works for you.
I found Cineform a fast transcode and file sizes about the same as AVCHD and I push them pretty far in grading sometimes. I didn't see enough of a difference in DNxHD to warrant the larger file sizes or time. But again, it's not going to work a miracle on what you capture, you still have stuff baked in that won't come out.
And like Dan said, I've done many of edits in AVCHD natively in PP and then output to what ever format/codec I've needed.