I had a new Carver C34 with a gas Kohler 7.5kw genset. I had nothing but trouble with it. Not even the Kohler tech could figure out why it acted as if the starting battery was dead the next morning while on the hook. The remote start never worked either. It was also very loud. I assume that was due to the high revving gas engine. That and other issues were why I sold the boat after two years and bought my NP45. Everything worked right from day 1 with the NP45. I'm very happy with it. I have a Northern Lights 9 kw diesel genset which, works like a charm.
I don't really think it's fair to compare a gas generator to a diesel one.