I have a Rift. My experience so far:
On the positive side, it is really quite immersive and a lot of fun to fly. I 'feel' the plane a bit better and the overall experience of flying is much better than I thought it would be. Another positive is that because of that better feel for the plane landing rounds on an enemy appears to be easier, perhaps because you are in a more intuitive, more 'natural' environment with VR.
On the negative side, there is the issue with graphic quality. I do not suffer from the well documented 'screen door' issue but the graphics are a long way behind what you get on a normal monitor or TV. Having said that, I do not find that a show stopper at all and it is very easy to get over that and immerse yourself into the environment. Where the poor graphics do cause an issue for me is in things like not being able to see hit sprites. I prefer not to use tracers and hit sprites are an important indicator for me so a lack of that feedback affects my game experience. That said, I have not applied any 3rd party fixes or tweaked my vid settings as yet.
A drawback to the immersive nature of the Rift VR is that your eyes are encased in the headset and that leads to a reduced ability to interact with your controls, from the keyboard and mouse to HOTAS to additional button boxes etc. Even just having a drink while you fly or looking round at something your wife wants to you give an opinion on is impacted by wearing the headset. A rather obvious thing but one worth mentioning. I find it very hard to interact with the community on the text channels while using VR. There are controls in place to aid this however, they are not as easy as just hitting / and then typing.
For me the biggest negative, coming from using a Trackir for the past 10+ years, is the difficulty in keeping track of an enemy plane using head movement ONLY. If you are used to using hat switches to look around then VR is going to give increased options for tracking however if you are trying to track just using your head movement you are going to need to be very supple.
In closing, if you have the money to drop on the VR and not be too worried about if it works well in AH or not, my advice is to go for it. It works very very well in driving games and for me it was worth it for that alone. If you are hoping to take AH to the next level with it, I think you may be disappointed. That IMO is not a fault of AH, just the fact that at present VR does not seem to deal with peripheral vision well and so to see behind you then you need to turn almost completely around whereas in real life you can achieve a 180 view even with your hear turned just 90 degrees, in fact you can see further than 180.
Early days. Without a doubt this is the future so again, if you are in a position to spend then spend, if this has taken you 2 years to save.....nah, I would not do it.