New MacBook Pro USB 3.0 and Super Drive transfer rate ???

The current $80 super drive that is out right now, it's only USB 2.0 correct, or did they upgrade it to the faster USB 3.0? I've never used any external USB DVD reader/burner before so I'm wondering if there's a difference in performance vs an inboard sata DVD reader/burner? Is it limited by the speed of the USB port or the read/write speed of the optical drive itself? Any gurus out there with an answer?

Here's another question, will any external USB DVD drive work on the MacBook or does it have to be "specific" to Mac OS? I was reading on eBay and this guy is selling his SuperDrive because it won't work on his Mac Pro and that the super drive will only work on the MacBook Air. Is this true? To me this doesn't make any sense. It's an external drive, what special driver does it need? Don't they all use a generic driver? Is apple so specialized that even their hardware is specific to certain models only?