We were camping with friends for the last few nights, and they have a new Jayco 5er with a Coleman air conditioner. It's a lower profile than the Dometic on our Bighorn so it has that going for it. It's also quiet when inside the trailer. That said, when you're outside the thing is insanely noisy, so much so that when on a recent trip it was apparently bothering neighbours. Another friend with another Jayco, same thing. This friend is now actively looking for a fix for the noise. I would suggest steering clear of a Coleman air conditioner.