How much work has he had since leaving the track? Or is he still on it?
He looks nicely uphill in this picture - but he's standing literally on a hill. You may find him ever so slightly croup-high in person, which isn't a deal-breaker unless you plan on contesting Badminton with him. Pretty nice shoulder angle, and a good set of the neck.
His front legs are a little odd to me. He looks almost slightly behind at the knee, and that couple with those upright pasterns is enough to make me question him. That said, it's kind a wonky angle, and the knees could well be fine. I will remain steadfast about those pasterns, however.
I like the length of his back, but his hind end is weak. He has a set-back croup, which means you'll have to really work on strengthening both the hind end and the back - definitely no riding the front end with a guy like this. Lots of hillwork, conditioning trot-sets on varying terrain, and CORRECT long-and-low. The pasterns in the hind have the same issue as the front.
We can't see his hooves from this picture but when shopping for an OTTB, looking at the feet is INTEGRAL. An unexperienced eye (for TBs, specifically) will see what us mere mortals won't.
If you go to see him, please bring a very OTTB-experienced trainer with you. Ex-racehorses are amongst the hardest horses to shop for, because 99% of people don't know what they're looking for with this specific type of horse.
Have you ever worked with a horse straight off the track before? If you haven't, don't do it alone. It's a lot different than working with a greenie. I always recommend that people pass on straight OTTBs until they have assisted a professional with several. You literally cannot learn it alone.