I tried it out and I got a pretty good result, but the problem is that I cannot copy and paste Match Color attributes. Say I have a talking head and use Match Color on some other random clip and get a really good result. I cannot duplicate this on all of the other clips of the talking head in the timeline without doing it one by one hoping I land on the exact frame I originally matched... can I?
I've occasionally tried to use it and always got pretty bad results, probably because you can't do much with DSLR footage. I think it would probably work really well with the RAW footage from my Pocket camera, but uhh, FCPX doesn't handle that footage so I can't try it. I'm curious about R3D raw footage now though.