Well, honestly, no generator no matter how quiet is gonna make the neighbors happy if run continously. With that said, I have the Champion 75537i, and it is pretty quiet. I can barely hear it inside the trailer with the air running. It may not be quite as quiet as the honda's/Yamaha's but at a fraction of the cost, Im ok with that.
I purchased this generator for the occasional boon-dock when there may be no neighbors, or the weekend tailgate where everyone is running one, or for the occasional power outage at home to power a few selected items(gas furnace, refrigerator/freezer, TV, etc).