The first Sam VR game was the character stuck in the same spot, you moved your head to look around, and your arms to independently aim two weapons.
The next one they got two movement options, people seemed to think jumping/climbing ladders etc was very natural to do.
Apart from mouse movement keyboard is generally very digital (on or off), having that fine tuning might take a bit of getting used to?
I still remember learning to play an FPS with a mouse, took a few months until I was better than just keyboard only.
I'll reserve further comment till I've tried it personally.