I startet nitro-racing about 5 years ago, having a history in electric r/c of app. 15 years though.
A buddy of mine is a pro-racer and he made me try nitro - i'm so glad, he did!
From the beginning, I've been using RB engines an i love 'em! Absolutely reliable, plenty of power (always been running the WS7 line of engines) and reasonable fuel consumption. Tuning those engines is not s hard as i have seen on a lot of other engines, you don't have to be a graduated engineer.
From time to time i get interested in engines of different brands, but i always end up with an RB again. Simply because they work as they should!
Just my 2ct
(and NO - i don't get these engines from my buddy, mentioned above - i buy them!)