I agree it isn't scary - well any more than Haunted Mansion is scary (it's dark inside the ride as you know). The biggest problem I have with it is how rough it is - I don't enjoy that part at all. I found the Safari jeep ride in the AK to be rough/bumpy also (I had a serious brain injury a few years ago) but being outdoors and sort of seeing where you're going makes that obviously not scary in the same way dinosaur could be. I can still ride Everest though - once or twice. Space Mountain is also very rough (jerky) so I don't do it either and Star Tours usually makes me nauseous but I'm fine with FOP or Soarin.
I would pick Everest over Space Mountain - unless you're fine with rough/bumpy. You're also in the dark on SM while Everest is outside of course. I find Everest to be just about my favorite Disney ride - I love going backwards apparently - lol.