Wow. I just found this thread while trying to solve this issue on my computer. I didn't read through the whole thread yet, but I wanted to add my experience. I bought a new Retina Macbook Pro 13 in February, and almost immediately had the freezing issue. I contacted Apple Support online, followed their directions, and encountered the issue again a few days later. At the end of March I finally made it in to the Genius Bar. After running all of their tests and finding nothing, they un & reinstalled Maverick, and said that if it happened again I should bring it back and would probably be given a new computer. Well, it happened again, so last week I brought it to a different Apple store known in the area for their superior service. Unfortunately, I had an awful Genius Bar experience, with a rude Genius who barely paid attention to what I had to say, and insisted that it had to be an issue with my router. As directed by the Genius, I called AppleCare, who said it couldn't be an issue with the router, and directed me to erase everything (I had transfered everything from my previous computer) and reinstall again. After this did not solve the problem, I called AppleCare again, who said that they could not solve the issue and directed me to go to the Genius Bar again. At this point I was fed up, especially after the really negative experience I had had at the Genius Bar, which I had communicated to Apple in their feedback survey sent after the appointment. I suppose my complaint was forwarded to the Apple Store, because I received a phone call offering to replace my computer.
I received a new Retina Macbook Pro 13 yesterday, and it just froze again. From the little I have read on here, I assume there is not much I can do at this point. I just disabled hardware acceleration in Firefox, so maybe that will help. Hopefully this issue will eventually be resolved. It's really unfortunate, because my entire family has been Apple devotees for many years (my father bought his first Mac in the 80s,) and this is the first time we've had any serious issues. This situation is really making rethink my loyalty.