This stallion looks gorgeous... he does have great hair and conformation, but he looks a little high-strug to me. In all of the pictures, he looks very, very alert-although well behaved, but that's hard to tell from pictures- but again, I wouldn't trust his temperament. Maybe if you called and asked for a video or two to be sent to you, that would be really helpful. You could then assess his movement and temperament as well. I'm not too sure about the ad either, though... $400 is a VERY inexpensive stud fee, and if he is deceased and as fantastic a stallion as he is portrayed to be, it should be much more expensive. You never know, though!
Sorry, I kinda rambled on... hope that helped, though!