I am not sure how much of a fan I am of TB's...since I have never rode one.
I might be soon though. My wife has one, and it might become my trail horse.
That being said...one of the BIGGEST complaints that I see here is from one of the biggest mistakes people make with OTTB's...and that is trying to ride them too soon after they come off the track.
The life of a Track horse is so totally different. They have never been taught to be ridden really...they do nothing but train really...hardly learn any maners at all. This is a gross generalization I realize....but true of MOST OTTB's life. They (and we...we have rescued several now) suggest that you give an OTTB about 6 months to decompress, and to get used to life off the track. Hand walk, groom, etc...but don't ride. Then when you are ready to ride, kind of start over almost like starting a young horse.
Everyone that we have done this way has turned out great. Good minds, and no buck offs no issues. One is doing mounted shooting, one is at a jumper barn, one does fox hunts...and the others are pretty much just companion animals/trail horses. Just something to keep in mind.