Same as above, due to personal experience. My sister had a mare who was perfect inside a show ring, or any type of ring for that matter and had spent the first 12 or 13 years of her riding career as a show horse until we bought her. The second she stepped outside to go on the trail, she was a bundle of nerves and spooked at everything including lumps of dirt, rocks, trees and was a total klutz! Even after getting more trail experience, she was only OK and luckily, trail wasn't the only thing my sister used her for.
I'd keep looking. While this guy doesn't look terrible IMO, I think you could find something a little more suitable to what you're looking for. Plus, to me, he doesn't look all that comfortable to ride.