I use Rotella 5w 40 full syn oil all year round. It exceeds all mfgrs warranties! In my area it gets to -10-15 below 0 to almost 100 degrees in heat of summer. Been using it for over 10 yrs in all my toys with never an issue. In fact nver heard of any issues with Rotella full syn oil....
You won't have any issues, it is actually a Diesel motor oil which works great for small engines with/without a filter. People have been using it in expensive motorcycles for years.
Just keeping the oil clean regardless of brand will extend the longevity of a engine.
A lot of people use Amzoil products as well.
Motorcycle specific oils are excellent as well just more expensive and contain anti-sheer additives for the transmission which scooter's don't utilize.