Yes, I have one on my Mainship Pilot 34. It is noisy due to the putt-putt nature of a single cylinder engine, but it is mostly exhaust noise. Vibration isn't bad as the engine mounts do a good job. I can certainly hear it in the main cabin but not objectionably so. I have the enclosure.
The bones of the unit are rock solid: a Kubota block and a Newage/Markon 5KW generator end. In addition to the mixer which has been replaced with a better design, the only other part that routinely fails is the excitation capacitor, particularly if you don't use an auxilliary blower. I keep a few spares on board.
One other quirk is that it does not have a DC alternator to charge the starting battery. I just use the Echo Charger output on my Freedom inverter/charger to keep it charged and isolated. A shore power charger with three outputs can do the same.
It will start and run our 12,000 btu A/C and probably a 16,000 one. I can only run two out of five heavy current appliances at one time- A/C, cooktop, microwave, water heater, coffee maker. So I have to juggle the loads but it is not a real problem.
I just use it to make hot water for showers, coffee in the morning, charge up the batteries and sometimes use a burner for dinner or zap something in the microwave. So, no overnight running for A/C. For that usage profile it works great. If you are going to run your A/C overnight for many days on the hook, then consider a 3 cyl genset.
David