Rider is not a bad rider just looks to me like he has not got the best balance and hands but in the video you can tell the rider also does not know how to ask what he wants out of the horse. (dang kinda makes it sound like I am saying he is a bad rider now :) o well)
The way I see the little guy is he def needs to learn how to SIT going in to the barrels he is dropping into the 2nd and 3rd but with a good rider that knows how to keep his sholder picked up that should be easy to fix he is just young and still on the green side, by green I mean inexperienced. He looks like he is a little heavy in the mouth if you watch close you can kinda see where the rider is having to kind of pull him around, but like most horses if you put them in the right bit then that problem is MOST of the time fixed.
But I think he is worth looking into, I do not know about the price they are asking for him but I am not from the area so I do not know what they run for that way, a horse like that in my area may run for about 2500 - 3000 so not that far off I guess.
But if you are looking for something with 1D speed your best bet is to find something already being showed and something that is already running those times.
Not saying he does not have it or anything, from the video I do not see it but like many younger horses they do not realize how to apply that kind of speed with brains. A lot have no idea they can go faster then what they think they can :), that is why seasoning a young horse is always so up and down you have to help them find their pace.
But all in all he is very cute and would be a nice addition to anyones herd if they were willing to further his training and kind of go back to the basics, but if that is not what you are looking for then do not get him!
In ref to the other question you asked about your mare, well I could never sell my mare, and I hate that I am not being able to run her right now due to an injury. I am picking up my new boy monday and it was either sell her or use other money and I could never ever ever sell my mare.
I was offered some big dollars for her in the past and without a pause siad "NO! She is not for sale :)". She only runs 3D/4D times could be a 2D horse but I have not been able to get a good whole year out of her due to, well, injuries :(. My new addition is def a 1D/2D horse so I will have a good set when I bring her back :)