A:Answer Great question because it made me forget to add something to my review.
YES, no problem switching between surfaces. I have many "saddles" between rooms at the doorways, up to 2" in height. It can get over them with a big BANG as it drops over them, but it can do it. As far as carpet pile height.. I have one with about an inch high and it doesn't slow it down. I can't give a cutoff point tho, you'll just have to try it.