punkey71,
Having owned and currently owning 6 YS engines, I would HIGHLY recommend them. The reason for using the YS's for me is simple, reliability! They are not completely set&forget but I don't worry nearly as much about the aircraft completing its flight if powered by a YS. Most of our, (my son & I), experience has been with the 1.20's but also have a .91.
The "tinkering" is minimal and well worth the time and effort. Just keep the basic "maintenance" parts on hand, (plungers, springs, diaphrams and OS F plugs - they cost more but you'll probably use -1- all season!
My personnal opinion
Steve
Puckett Model Aviation