Unfortunately my last seasons experience ended up like this
but besides that, it was an excellent engine.
It holds tune really well and has tons of power. Also it is not so sensitive to needle settings as red dot. I would call RB R3 as a really work horse with plenty of controllable power.
Of course, there are many success stories of well going red dots, but from my experience, in average, you will get a lot less trouble with R3 than red dots. Besides that R3 is bit less sensitive to temperatures and doesnt have conrod snapping issue.
Even though my 3R crank case broke on the last race of the season, during 10min before a final, im still very happy with performance and will use it for next season as well.
300$ for it sounds to be reasonable price