I've camped next to others in campsites with the Yamaha 2000is, and there is an absolutely obnoxious "pulse" or "popping" noise sound to the exhaust tone on them. If I spot a campsite available with a neighbor running a blue Yamaha, I will pass on the site and find somewhere else. It was really obnoxious, the exhaust sound of the Yamaha. YMMV, I don't find the Yamaha's to be quiet under some load in eco mode. Possibly something to do with the compression ratio being so high, or the motor works very hard in that capacity.