For part timer Grab will be better. You can pick and choose your trips like teksi driver. Yes a lot of part timer prefer Grab because of this feature and then end up complaining when Grab trying to enforce people from picking and taking only the trips they feel worth it.

Apart from that, with Uber the unknown rider destination is a hassle. Example below:

You stay at Gombak. You online plan to drive from 10PM to 12 midnight, then need to rest for tomorrow daily work.
With Uber, you can end up in Cyberjaya in the end. And then drive all the way back up north. Yes, you can set destination while driving back, but you can experience it yourself whether it is worth to use set destination which sometimes divert you to a short trip and you are actually wasting more time. Remember you need rest to work in office the following day.

For full timer is okay. You drive the whole day. You dont mind even end up in Banting or Hulu Langat or Semenyih for example.