I'm (now) using GC all the time and wouldn't want to be without it.

While one can get a pretty decent render out of PP-2012 without GC with just as few lights as with GC, SSS is truly boinked without it.

So, it is possible to go without it, but if you want to have the best skin possible, you should start using it.

BTW, it's always amusing to see how fiercly people argue over features that are only really needed to achieve photorealism, while there is not a single commercially available figure out there that would actually warrant all this extra effort.

;-)