Okay, after a second look at the video, I see a horse that's very quiet and workmanlike, that keeps a good steady rhythm to its fences, is ratable and adjustable and is tolerant of a rider that doesn't seem to know how to sit and whose aids are primarily in her hands. I also see a horse that's very honest and jumps from a variety of distances.
I will say that she also travels fairly hollow and inverted, and doesn't bother snapping her front in if she gets to a weak spot.
It's also possible that she's a little cold backed and that's why the rider is staying up off her back; but I don't think so - I think it's a rider who's used to cantering in two point and riding off her hands.
Overall, my initial impression of her stands: probably a very good, safe choice for someone who wants to start off in the Children's/Junior's Jumpers and have a good experience. I won't comment any further on the price since I'm not familiar with your area; but around here it would certainly be considered reasonable.
I suspect folks who think it's unreasonable are either in an area with a very different horse economy and/or aren't familiar with the cost to lease a reliable packer capable of going to rated shows.