My 2 cents:
I absolutely LOVE the ride. I am not a super-thrill ride person, however I've done just about all the thrill-type rides at WDW, and love them all. However, trying to be fully objective - Everest is definitely one of the more "smooth" roller coasters, definitely much less jerky than Space Mtn. However, I'd personally rank Everest at the highest intensity of all the roller coasters. With Everest I get that feeling in my stomach, particularly at the backwards portion - and I did not even get that feeling on Rock 'n Roller Coaster. I personally don't mind that sensation, but I would say that Everest is the most intense.
My father's perspective - he loves Splash and Big Thunder, but stopped going on Space a few trips ago because it is too jerky. He just tried Everest for the first time, and I don't think he'll go on it again - a little too jerky and too intense for him.