The new boat will have an 1800 rpm Northern lights 6kw generator.
I installed a 3600 rpm Fisher Panda 4200 Plus on our sailboat a couple of years ago. I know that people go into convulsions at the thought of Fischer Panda but I rather liked the little unit. It was nicely made, it had decent documentation with enough information that I could understand how it worked, it was actually very quiet, especially compared to some of the other small generators and it took whatever I threw at it for loads.
I've been aboard an American Tug 395 when the generator is running and there is no question that the Northern lights unit is quieter and does not have the "buzz" of the 3600 rpm unit. I did not find either objectionable...
We had put less than 200 hours on the FP before trading the boat in so I can't be of help answering questions about durability...
Bruce