[Jeff Kirkland] “I usually use EditReady to transcode or rewrap the files to a new folder, then import the new files rather than getting fcpx to do it.”
I strongly agree with this. Re-wrapping (not transcoding) with EditReady is very fast. Importing the resultant files with “leave files in place” is super fast. It avoids issues with bloating the library and possible problems with aborted ingest which leaves camera icons on some clips. That problem is so frequent I see it reported on various forums about every other day.
With some codecs such as Sony XAVC-S you can get away with copying the .mp4 files out of the tree and importing with “leave files in place”. We know from experience this works OK with FCPX (at least current versions).
However this is generally poor practice because the files are not re-wrapped and for some codecs the behavior can be adverse. E.g, doing that with AVCHD can cause major performance problems. Other codecs might need metadata info about clip spanning, color profile, etc. EditReady folds all this into the re-wrapped file.