Honda EU3000iS vs Yamaha EF3000iSEB?

Also, being able to adjust RPM as described is pointless since all generators have to run at a set 3,600 RPM in order to produce 60 cycles per second. Anything above or below that won't produce a proper sine wave. Also the reference about difficulty in rejetting a carb for altitude is over-stated. The float bowl comes of with one fastener and the main jet is at your finger tips. Any engine, properly jetted will still lose approximately 3% of its available power for every 1000 feet of elevation, so that's also an issue for running and powering something at the rated load at high elevations.

Another consideration in choosing a generator is whether or not it has a forestry approved spark arrestor since any federal land prohibits running one without one (National Parks, National Forests etc.)