I was evaluating this issue several months ago before we took our trip to Alaska. I think it depends on what you want to power with your generator. If you want to run the lights, refrigerator, TV etc, you could easily get away with a 1000 watt unit either Honda or Yamaha. But, if you want to operate your microwave or AC, then you are going to need to go in one of two routes. The 2000 watt units are bearly enough at sealevel and if you have any altitude at all they will be insufficient. (I am told they loose 15% of their power per 1000 feet in elivation.) Therefore, you will either need to get another 2000 watt unit and hook it in tandem which both Honda and Yamaha can do OR you can get the Yamaha 2400is unit which can handle a 13,500 BTU AC or microwave without any problem.
I went the Yamaha 2400is route because I did not want to have to deal with the maintenance etc. with two units. The Yamaha 2400is is alittle heavier (70 pounds) but was not moved to hook my power cord to when needed. I hope this helped.
The question I have for the forum is whether the Yamaha 2400is unit will power a 15,000 BTU AC.