I have a personal love of thoroughbreds. I've owned 3 OTTBs (all chestnut mares too, which are supposed to be crazy!)
Indi - Best horse I have EVER owned. Was the perfect trail horse. Never put a foot wrong, only ever wanted to please, but still had her own character (never became an automaton). She was very easy to train, and I voice trained her in a matter of days, so stop to canter was easy, and canter to stop was equally easy. Great gallop because of her racing past, but good brakes too. Never rode her in a bit, even on the trails. Not only that, when I got home, untacked her, and turned her loose, she stayed by my side. I'd just stand and hug her, holding her head and kissing the op of it. Such an incredible bond we had, and I will never forget her.
Tilly - racing sadly ruined this poor horse. She was very unpredictable, even though she would follow me around like a puppy, and beg for attention, I could never trust her. She was incredibly spooky, and I never had her attention. She had some distressing habits that she'd picked up the racing yard. She minded me a lot of Scooby Doo, but 16.2! Just a bit dopey and silly, spooky and funny. She certainly had a character, but I never really trusted her because of the dumb things she'd randomly do.
Velvet - Velvet is lovely. I got her in early September. So far she still has some of those racing tendencies: A little spooky, "looky", fast and every time I try to do join up with her, she thinks I've hooked her up to a walker, and will go around, and around, and around (it actually gets so distressing, I can be waving, saying "whoa", shouting "whoa" and she just keeps going at the same pace, vacant look in her eyes. To the point I don't enjoy trying to get a join up with her, because she does this, very distressing. I believe it's because she's just been put on the walker frequently). She is very intelligent, but doesn't abuse that (some horses are smart and if you don't challenge them they get sour, well, not her) I do clicker training while the weather is bad and I can't ride, and she's quick to pick new things up. She's very loving, and although she was very uneasy being touched when I got her, she loves to have kisses on her muzzle now (and I love giving kisses on her muzzle!) So far I have taken her on trails as I haven't had chance with the bad weather. I'm itching to go though!
I think you can find a nice horse of any breed, but I have a soft spot for the old tb. Good luck in your search, and remember, always get the horse vet checked before buying (speaking from experience. Race yards will do anything - drugging Etc - to shift a dud horse at your expense)