Is the Indy guy an HVAC guy, or just some guy that works with a plumber that is doing this as a side job? He's a licensed contractor? If so... go with him.
I'd ask the indy guy if he can offer a decent maintainence insurance on it. While most of the time they are mediocre, at times you can get a good deal and some piece of mind that you won't be forking out for addtional costs later on.
