I'm still an old school guy. We always mounted our engines as solid as possible. I was taught that an engine that wasn't mounted solid was not as effecient as an engine mounted securely. Some modelers wouldn't even think of using a radial type mount and used hardwood engine bearers to let the fuselage absorb the engine vibration. Besides, most all the modern engines run pretty smooth. Like I said: this is what I was always led to believe and will probably never be convinced of anything different. Just my opinion.
JERRY