There are advantages to both.
With the P2V+ you get an 'out of the box' quite good camera, very good gimbal, quite good FPV via smartphone/tablet.
The video quality is adequate for youtube but not up to (recent) GoPro standard.
Another snag is the camera gimbal assembly is an all in one unit, which is somewhat fragile and expensive to replace.
For better video, especially if you already have a GoPro or would use it off the Phantom too, you can take that more modular approach and get a P2, and 2d or 3d gimbal and attach your own camera.
If you want FPV that's an additional item, if you want flight data about altitude, speed, battery and satellites that's another problem area compared to Vision and Vision+
The GoPro setup will cost you significantly more to get similar features to V+