He's a good looking horse and while $1200 is fair for a horse that's been shown a little and started, I'd sure be offering a whole lot less if I wanted him.
Crabbet/Egyptian Cross = a lot of people won't even look
Green under saddle, doesn't show that he has real accomplishments (everything is listed as PROSPECT, not saying IN TRAINING FOR, Has been in training for XXXXXXX for XX amount of days and has accomplished XXXXX)
Make sure you measure him yourself, stick & level on concrete or asphalt, just because of the notorious "Arabian Measuring Stick". Can't say how many times I've gone out on a 15.1 or 2 horse that was barely 14 hands.
Check his conformation carefully, he's a handsome looking horse but those are not good confo pics, so check his legs and feet really close.