The 4300 is a 10.5 motor. In fact, Novak dropped the 4300 name a while ago in favor of calling all their motors by the number of turns, which seems to have become a standard with sensorless motors.
I haven't compared these two motors. One thing to keep in mind is that the Novak 10.5 now has an optional 13mm sintered rotor which may improve its feel, and possibly performance. The Orion (Feigao based) has no such option at this time. I have compared the 13.5 versions of the two motors and didn't like the feel of the Orion at all.