The inverter type generators are the best and quietest out there but don't overlook altering the exhaust on any generator to quieten it down a little too. A simple insulated box type of cover can also help if you leave enough ventilation and can build one that don't catch fire, the noise can be made directional with the right enclosure.
You'll get plenty of responses on which one to by, just cut to the short of it and go Honda.
