I'm a Mac guy and so I decided there was nothing for it but to go from Mavericks to Yosemite. But to be careful, let's first do it on my Mac Air. Hmmm, loads all right but Manga Studio is VERY laggy and I got a message that the Wacom driver was trashed. Lag due to the trashing or the OS? Don't know. Soooo, let's do a full TimeMachine backup of my main machine AND a SuperDuper backup. Okay, done. So now lets put Yosemite on. Did it trash the driver? Yes. Is Manga lagging like crazy? Well, okay, not "like crazy" but the lag is highly obvious, persistent and quite annoying.
So what's the conclusion? TimeMachine is purring along bring me back to where I belong. To Mavericks.