If you have the rift or vive and own FSX, the flyinside software is a no brainer must have, even if its not perfect, - it gives you that option to use VR when you want and one of the great features - If I want to play FSX without using VR, my original settings are left as they were in dx10 maxed out. My favourite plane to use in VR is the A2A piper, looks amazing as it has all 3d panels in the VC. Its pretty hard to fully sim a flight in VR with complex add on aircraft. Looks amazing and more stable with that setup. If Im not in VR my FSX sim runs in DX10 preview with steves fixer. Also whilst using VR with flyinside it reverts the sim back to DX9 graphics which uses a lot more memory making the sim more unstable than it usually runs in DX9 without VR. I fly the PMDG Airliners so using VR with these proves to be somewhat difficult as you need to set up the plane with the CDU etc. VR in FSX is great if you only want to fly GA planes or the default airliners. Its a great program and fsx does look and feel more immersive when flying in VR, but there are drawbacks. You can download the demo which only gives you 15 minutes for free.

Microsoft flight simulator 2016 vr