I can't say for certain that they are the best, since I haven't travelled on other lines, but the Auto Train crews are great in my experience. They deal with a somewhat difficult customer base (seniors traveling from the Northeast to Florida and tourists to Disney) and maintain their dignity...
The first thing I do when I get into my room (I always get a sleeper) is bring out the Lysol wipes and start cleaning. I don't care how clean it looks-I'm a germaphobe.