I had a 2000 Champion many years back and absolutely loved it. I used it to run my bus, which really only ran the amps to power the speakers and sub along with our satellite and 2 TV setup.
My brother in law has the 3100 Champion and has used it for his camper for 5+ years. He has a 30amp service on his with no issues. He has even had a few things go wrong with it and Champion has been very good about sending him replacement parts at no cost.
I got 2 3500 Champions last year, hooked them in parallel, and they ate thru the gas powering my camper which has a 50amp service. I don't know why they ate thru so much gas, which I didn't like, so I sold them this summer and bought the 7000 Honda and love it.