We did the alpine slide at Oberammergau (Kolbensattel) and had an absolute blast! The lift to the top is very pleasant and the view is wonderful. The slide itself is on a track rather than a luge. The course goes through the trees and is thrilling but not scary and absolutely beautiful. We loved it so much we took a second trip! If you're looking for a thrill and a view, this is your best option.
Tegelberg is a beautiful area, and we love to spend the day hiking and watching the paragliders. The slide there is in a luge track and curves back and forth.
I'd recommend you do a search on YouTube. Several people have posted videos so you can take a virtual ride down the mountain and pick which one you like best!