One good reason for going with a Yamaha 2400 watt unit is that the 20 amp capacity unit will start and run a reasonably sized roof air conditioner a little easier than a single Honda 2000i, and avoid having to put your total generator demands/needs in quite as much jeopardy.
Two Honda 2000i's will do a lot more, of course, but then you've got two units to plug together and find the room for, plus two times 46 lbs, or 92 total. The Yamaha 2400 is no lightweight itself, coming in at about 67 lbs, as I remember.
Joe. :teeth :thup