Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I had/have a similar problem when I plug something in the usb port (doesn't happen all the time). Power key still works tho.

(13" retina mbp late 2013)
 
Happened to me one time on my late 2013 15" when I was using 10.9.1. Since installing 10.9.2 the computer has never totally locked up although I get some application stuck (spinning beach balls) problems with the Adobe Premier Elements 12 video editing program which is very likely an Adobe software problem rather than a Mac OS problem.
 
Yes, power button still works, as the only way to get it to work again is a hard reset.

I'm using 10.9.2, it fixed the reboot while sleeping problem, but NOT this. Again, this seem to be an EFI problem, similar to that reported for 13" rMBP, but EFI on late 2013 rMBP was never updated!
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.