This is just my experience, but there's an HDR at my barn that I've ridden in a few times that I hate. I don't know exactly what model it is, but I find it so hard and uncomfortable, and it puts anyone I've seen ride in it in a chair seat. On the other hand, I have a good friend who was saddle hunting for her guy and ended up buying an Ovation after she rode in someone else's and fell in love. I don't know when you're buying, but I'm probably going to visit her next weekend, so I can offer what I think about it then.
As it is now, I'd definitely pick the Ovation over HDR. Just my two cents!