I know this comment is coming quite late, but for anyone interested in the same question... My two cents:
In terms of feeling, having used both, I find that the RF is a lot snappier, a lot 'crisper' if that makes any sense. Also the board felt a lot more solid. All in all a better feeling.
With that said, I went ahead with the fc980c, for a couple reasons: 1) While not as snappy, still a great and solid feeling 2)the layout intrigued me. took a bit getting used to it, along with remapping some keys, but now ok 3) was buying in Korea - the RF was just crazy expensive... there is such thing as too much $ for a board.