Those are certainly good choices, albeit expensive onces. The OS engines, from everything I've seen, are the ones that you can trust to be trouble free nearly every time. I have an Evolution too that has given me its share of fits, but it does run well now. The engine I'm sold on for future use though is the Magnum 2 strokes. Mine has been as trouble free as any O.S., so for what they cost I'm hooked.