Couple of boats I've sailed on owned Honda gennys. Thats the only recommendation i can give. One of the boats was owned by a commander RN, a very capable chap, and i dont think he would have anything not up to the mark.
Expensive compared to most, but they have a fine reputation for reliability, and i suppose thats one of the most important factors.
We've got a 6KVa Honda powered generator. But bought probably 15 years ago for £500. Runs everything whenever we get a powercut. In five minutes, I can get the house switched over to it and then carry on - busy as usual. Starts first time.