For those of you just reading the last 2 pages or so, the AT is fine. Some people have bad experiences, but for the most part, reviews are good. My family has taken it several times, without any horrible experiences. Once the engine did break down, we were up and running in about 2 hours. My in-laws take it almost every year and we are taking my parents with us this year. We stay in coach, don't feel the sleepers are worth the extra money. The ride to Disney is easy from Sanford, usually traffic is gone by the time you get your car. We are usually in parks by early afternoon.
Of course, I am careful with valuables. I usually lock them in my luggage in my car. The kids are responsible for their electronics and one of us usually stay with our stuff except for dinner.
Hope this helps.