I concur with bobmacc's comments about the clearances and the "jog" required to get to the toll booth, we were fortunate there was virtually no other traffic when we crossed so it wasn't that bad. We cross at Detroit, we tried Port Huron a couple of times, easier but going through Detroit is a bigger hassle than the Ambassador bridge, one year we had a shovel of cold patch asphalt thrown at a pothole in front of our TV by a maintenance guy, we served as the roller!
One thing that the border guy did this year was different, he opened the slides partially to have a detailed look around, must be a new thing. He had us move forward so that the slide could be opened without hitting anything. I did a double check after he finished to make sure that everything was put back properly for travel.