There are benefits to using full-synthetic oils, but using any oil that has the rating your manufacturer states must be used will ensure the engine is safe.
I don't use the spendy stuff on sleds unless they have power valves. On the non power valve sleds, I use the cheap stuff from Wally World at 10 bucks a gallon. It protects just fine. It will protect a power valve engine as well, but you may have to clean the valves more frequently.
2007 RMK 700, 2008 RMK 600, 1995 AC Prowler 2-up, 1980? AC Cheetah