I have the VCC and the FG-X. They are both really good.
VCC adds a touch of analog non-linearities. Very subtle but also very effective. Don't know why, but somehow it's easier to mix a song. Seems like everything finds it's own place in the mix much better.
It's the first thing I put on the inserts of a track...
FG-X is a very good limiter which can preserve the dynamics even when hard driven.
If you have an iLok you should download the demos and decide for yourself.