John, I will say that adding cruise to my TMCC upgraded Gallopin' Goose made a big difference in running, and it doesn't pull anything. However, I have to agree on stuff like Trackmobiles and speeders. First off, if you run those all that much, you'll find you're putting in new motors a lot, those little flat sided motors they use do not have a long MTBF!
My MTH DC-3 has cruise from the factory, and so do the two Doodlebugs I have.