I just purchased a pair of Yamaha EF2000is and the jury is still out. I had an issue where they would not start my AC until I loaded them up first. I don't know if it is because they are new or if it is because they have some issues. I called Progressive Industries to make sure it wasn't my voltage protector and he said that the Yamaha's sometimes have an issue like that...but again it was only hearsay for him and he doesnt know if the reports are from new or broken in units. I will continue to experiment with them and I will be installing a Hard Start capacitor in my AC unit.
I also have an EF2400 which I feel worked very well, but I wanted more power so I went with the pair of 2000's. The Yamaha's have more features than the Honda's and double the CARB life so if I can get past this issue I think they are the better generator, though the Hondas are reportedly great too.