I think it depends on height if you can survive an intamin. I found collossus painful when I hit my ears and side of head on the restraints (who thought they were a good idea?).As above, Colossus features in my top ten. Roughness doesn't bother me that much, I can take a few knocks.
Another bad coaster (well, not a coaster really) is any disko. The ride is fine, but the restraints stop you from breathing.