My two Yamaha will do it at 6000', but they don't have a lot of reserve power.
The only advantage I see of the Yamaha is they have a fuel shut off so you can easily run the carbs on the generator dry.
The biggest advantage of the Honda I see is the ease to do an extended run tank.
I ended up with the Yamaha because I only wanted one and I found it used at a great price. Then needs changed.
If I were starting today I would go Honda.