1. Are you sure the RBM3 is not long stroke? I do not know, just curious where you got this info from. I recall reading it was long stroke.
2. Not to bash nova (I am a fan and for the past two years only have novas and nova based engines in my trolley), I know a guy who got the Virtus red dot and was quite disappointed vs the keepon and ORCAN GT3C.
3. I like the ORCAN gt3C best and the RS3 so far. Both are nova based but they require a very high level of maintenance (conrod) due to being close to the power and internal stress limits.
4. On any given day my favorite is a murnan 353C that is smooth and indestructible. Often, given thr mm353c's non-super explosive power I will run quicker laps with it.
I dont know if its long stroke or not.