I use Control V2 and I also used to use VSC-2.
Control V2 is essentially a M/S processor with a couple bells and whistles. It's a good plugin, though I have other tools that can essentially do the same thing. It's nice having all the metering under a single roof so to speak. I primarily use it to tame stereo heavy sounds or to center (monoize) the low-end of a sound to prevent any phasing issues amongst other sonic disturbances. My advice would be to read the manual first to really get the most out of it...I found that I was able to really put it to good use once I really understood how each component worked...and sidechaining signals was required (doh!).
VSC-2 is a VCA compressor based off of some legendary (and very expensive) hardware. It's good for mastering, though I used it for buss'. However, that was before I bought Cytomic Glue, which is now my go-to for buss compression.
Cheers.