That first mare, there is just something about her build that I don't like but I can't quite put my finger on it. I think it might be that her pasterns seem pretty upright and her feet look way too small for her body size. I would worry about her soundness under a competative workload. Plus, her stride is short and she's choppy around the barrels. I don't see her having enough speed to be very competative.
I do like the gelding "Reggie". He has quick turns (not terribly smooth around the barrel though) but doesn't appear quite as quiet as they make him sound. However, for a good rider, he might be just the ticket.
The palomino....eh. He fought the bit around the turns and didn't seem to know his leads very well because he crossfired a lot
between barrels. If you were looking for a project.....maybe. If not, I would pass on him.
That last one, the fact that the video didn't show him from the start makes me really wonder what his temperment is before the pattern
. Though they may not have been pushing him much, he didn't seem to have much extension on his front end. He was fighting his head a bit too and seems a bit iffy on his leads as well.
Out of all of them, I like the second horse the best by far. It looks like he could use a bit of finishing work but I can actually see some real potential in him that just isn't there in those others.