rb - one of the best, made in the same place as Novarossi.
os - great life, but not so much power I've heard.
picco - one of the best, balls to the walls power! Just poor carb design.
hpi - good for RTRs and bashers, not for racing.
novarossi - one of the best, wide selection choice.
Like it has been said, it depends on many little things like the way you break it in, how you drive it and how you look after it. Sometimes there is a defect - nothing/no-one is perfect, but it more or less comes down to personal choice.
Car-less (Velox V10 or 733) // RB T10.5"+" (JB Modified) // Bluebird BMS-990DMG (St) & BMS-631 (T/B) // ATS 16% // Capricorn Wheels // Protoform
"70% of the time, it works ALL the time"