If you fly competitively, you need both reliability and performance. The engine needs to be congruent with your particular application and perform as needed for that application. Reliability comes from familiarity with the engine. A competitor needs to be able to fly, either in practice or in competition, without having to fiddle with things. When all is well, I don't even hear my engine running. I am focused on flying the airplane, and ignore the engine which is out there doing its thing in a competent manner.