There is as far as I know no speed difference between working in degrees and in radians.
Though, Panda3D’s angles work in degrees only. For example, to turn a nodepath right, you would do nodepath.setH(90), or -90 for left.
The only place where you would need radians is if you are going to work with sine and cosine calculations, so if you need them, you will need to convert your angles back and forth.