reply to dennismurphy
Re: Decent 20-30 KW standby generator I'd go for Generac's crappiest air cooled model over any of the chinese diesel generators available. Who cares about the maintenance interval if the whole thing fails in the first 100 hours.
Generac, Kohler, Katolight, Onan are brands you should be looking at. 1800 RPM and liquid cooled will be a good combination to maximize maintenance intervals.