I've done Everest only once, BTMRR several times, and have never done Space Mountain.
Same here. We LOVE BTMRR and ride it several times on our trips (when it's not closed for a refurb, which seems to happen a lot). We rode Everest ONCE, and that was enough for us. I think it's much more intense. DD18 said I screamed thru most of it (which I didn't realize I was doing) and I felt quite dizzy when we got off. I can't get DD18 to ride it again, which is fine my me. When we were in line to ride it, they had a "code V" clean-up (vomit). I'm glad we tried it once but I have no desire to ride it ever again.