I'm personally a motorcycle fan myself. I think if you're going two wheels, you might as well get the real deal (just my opinion, I just think scooters are silly).
I couldn't really answer your question as far as safety, etc. goes. Scooter is probably more user friendly - you need a license for a motorcycle. I don't ride scooters, so this is just an assumption - but I assume scooters are more straightforward, while motorcycles need to be shifted and what not. I would also assume a motorcycle has better performance, but again, I don't ride scooters, but I can't imagine them going very fast, so I don't think you could go far. You'd be limited to back roads - certainly nothing on the high way. Again, I can't really say anything for the other questions. But, in the end, it's your personal preference and how you would want to utilize the vehicle.