Really, the best parts of the movie deal more with his struggle to find his musical voice, his own style instead of replicating other more established stars. His dealing with Atlantic Records and eventual move to ABC for more money and control of the music is also interesting, though I'd be interested to find out how much back story was left out.
Also, the movie makes it seem as if Ray's social conscience was nearly nonexistent until one sudden day in Georgia when he refused to play to a segregated audience. As a black, blind musician playing in Southern clubs, he must've been the vicitim of some pretty nasty discrimination and formed some thoughts on civil rights along the way. But in Ray he goes from Southern "boy," content to make a living playing the Jim Crow "chitlin' circuit" to standing up to the man in about 30 seconds. Some evolution might have been portrayed.
Some of the best secenes were of Ray and the Sonny Fulson band playing those Southern, black, clubs. Interestingly, I spotted two places within a few blocks of my old New Orleans apartment, the Half Moon and Saturn Bar. Whether Ray actually played those places or not I don't know; they may have just made good film and apropriately signaled that he was playing in New Orleans, but not many people would recognize these two places so I doubt the latter. Maybe they're just cool signs.
It's worth seeing, even if you wait to rent it.