Based on my experience, motion controls are much more fun and it's how the game is intended to be played, but pro/traditional controls are much more precise and you'll play better in general
Motion controls > Party Match
Pro > Ranked
More like, it's whatever you are use to.
After doing the grand Prix rank 4 with motion controls, I went to do a versus match with the Pro Controller and lost because I couldn't get use to the controls even though I tried them a bit during the test punch.
I didn't even like that I couldn't move and throw my punches in directions independent of my movement.
So I rematched, switched back to motion controls and won easily since I had better control of my punches.