Funny, I find gas motors to be the most annoying and a well muffled 2 stroke heli to be very quiet and tractable.
I ran a YS 91 ACH in an X-Cell graphite SE for a couple of years and liked it a lot but though it required much less fuel, it had its own problems. The motor runs hotter and it requires a governor to keep from over revving in aerobatics. The 91 performed well, was fuel efficient, and was very smooth but had nowhere near the performance of the new YS 80 2 stroke or OS and YS 91 2 strokes.
Gordie