Mt Hood Summer Ski Camp is legit as hell. I rode their park a good bit this past summer, and it was fucking FUN. They hands down had the best jump line on the mountain, and hands down the best vibe.
It was a 3 jump line, I think like 20 feet, 35, 50 or 60? I'm not sure on the official sizes, because they got smaller over the summer, but they were by far the dopest jumps around.
Also, they have a really sick single barrel handrail that is pretty long, and awesome to learn tricks on. The rest of the rails are mediocre, but still pretty fun. If you're trying to learn some shit on rails, you'll be able to, and you'll definitely be able to jump.
As for Windells, I don't really recommend it, it's way more $ from what I understand and they get on the hill late as fuck. Also, they leave earlier as well. You'll get much more riding in At MHSSC. Windells has some cooler rails, but they arent really shit you'll progress on. And their jumps are hard to compare to the perfectness and flow of the 3 in MHSSC.
Not to mention - Malone, Stu, Nolan and all those guys fucking kill it, and they're nice dudes too. Go to MHSSC, they might not have all the stupid perks Windells does, but odds are you will learn more. You're going to Hood to ski, not skateboard anyways, you don't need some huge retarded skate park...
This is just my opinion though, I was given the opportunity to ride both parks and enjoyed MHSSC's a little bit more. Don't get me wrong, Windells is sick, but I think for the time and money you'll be spending, MHSSC is unbeatable.