KonceptVulcanRentQNThere's really not enough of a difference between the 3360 and the 3310 to warrant buying a new mouse if the old one still works for you and you like the shape.G pro has a worse shape than the g403 and the g403 wireless is even better. The 3360 spins out way less but spinning out the 3310 is incredibly hard, so yes you don't need to upgrade just for the sensor
If you really want a 3360 mouse tho, I definitely recommend the Logitech G Pro.
Some people also have an issue with their technique of flicking the mouse, starting at an angle and then going flat on a pad. That could be a reason why he would want the 3360. Unlikely, but possible.
https://youtu.be/zbQv6P-oh-0
Also the shape of the g pro is really dependent on your hand size and preference of mouse shape. The g403 is much more ergonomic than the g pro so if that's what you prefer then by all means go for it.
The g403 is in general a far safer shape to go with than the g pro, and I would imagine that if he had a problem with it spinning out he would mention it