Which VR to choose from ?

There is no major difference. You can use one or another to develop a project for both headsets (but you’ll need to test you game with another headset anyway sooner or later).
By default, Oculus doesn’t support 360-degrees tracking with controllers.
By default, Vive doesn’t have motion controllers with fingers tracking.
In UE4 Knuckles and Touch controllers have different events for non-standard input (although I think they’ll be unified in a future versions).