Continuous duty means that the motor can run for more than 5 minutes without overheating. Continuous duty motors are the only type we will sell. Starting type applies to single phase motors only. Permanent split capacitor is better than shaded pole. Shaded pole motors are also less energy efficient.
Bearings are either ball bearings or sleeve bearings.
This is an important point in durability. Upper and lower ball bearings are superior. One ball bearing is next, sleeve bearings are lowest. Built in thermal overload protection with automatic reset is an important feature. It both helps protect the motor and makes it legal by the National Electrical Code.