It really depends on what kind of FPV flying you wish to do.
Most people opt for gimbal+FPV because they kind go hand in hand.
- FPV allows you to frame the photo/video, but without a gimbal the video will often look shaky and unstable.
-and gimbal without FPV, you're just flying around hoping to get the shot!
But there's another group of people out there who fly FPV without a gimbal, I refer to them as sport-flyers, they're the ones who fly fast, thru trees and other obstacles, doing loops and rolls. You can easily tell by the fact that the camera rolls/banks left or right as it's flying.l - tho sometimes the video might appear jerky or have a bit of jello.
some people fly with two camera's, one for FPV and another on the gimbal
But flying with two camera's can sometimes have it's disadvantages, as if you're shooting with a GoPro, but flying from the perspective of the FPV camera, you'll be unable to monitor what the GoPro is seeing (if it's tilted down enough, or even IF it's recording or not (easy to forget to push that button sometimes!).
the OSD Mark II has a remote switch you can use tho, to switch between viewing thru the FPV camera and a GoPro., but that get s a bit complicated (and also requires a tx with open channels)