I guess everyone has a different level for loudness. All I know is I got my Honda GX35 engine yesterday and fired it up this morning. Wow! What a difference. It's VERY quiet, and smooth as can be. Started on the second pull right out of the box, and after that starts on the first pull every time. Can't wait to get it mounted on the bike.
The only complaint I have so far about the Staton friction drive setup, and I think this applies to all of the other friction drives as well, is that the motor sits on the L side of the bike. I would much rather it set on the R side for that added stealth factor. Bill here on the forum says he has the belt drive setup from Golden Eagle and it mounts on the R side of the bike, so I'll probably go to that later on. He says it's the smoothest and most trouble free setup that he's used.