I just bought a late 2014 13" MBP with i7 processor and 8G of Ram to run FCP X 10.1.2 for use with a Sony A7 and A7S. I have had no problems importing the clips directly from the SD card into FCP libraries. I do dig into the card structure to find the mp4 files though. I don't need to optimize, and I don't need proxies. Editing seems very quick to this newbie, and everything is in the FCP library for backup. The files on the card are erased when I format, and the file naming starts again at C0001 etc. but the first thing I do when I add new clips to an event is to rename them to something that reminds me of the clip (i.e Hand shot).
All in all avery easy process, although I wish I could grade S log 2 better...
I hope this helps.
Michael
tealwayfilms.com