The fan really does help, it helps with keeping my glasses from fogging a bit too, I'm using an older pair with a poor coating, yet narrow frames which fits - contacts just don't sit on my eyes like they used to, but with them in, it's fantastic too.
Rich, there are a couple negatives IMO - if you're used to 1080, 1440, or 4k graphics, the rez is a bit of a let down, however, the effect of being "inside" the cockpit more, way more, than makes up for this. I also find that my air combat ability improves greatly in VR due to the positional awareness - it just seems like I can judge distance, speed, angles, all of it SO, SO much better. Also, for example, when on top and behind a con on the deck, when I roll over, I can see him outside of the top of the plane and side of the cockpits in such a better way, it's difficult to describe, but it's absolutely there. I've only been flying online the last couple days, having spent most of my time offline getting things set the way I like, but the VR experience truly adds to the situational awareness and..positional awareness I guess.
Just sitting in a Ta152 tonight on the way to the target base, looking around was truly a marvel - a real feeling of truly being "there".
So far as the airsickness/nausea, I've only felt a glimmer of it once, it isn't all that common so I wouldn't let that stop you. You have a good system for VR, we've got 1080, 1070, and the Pascal Titan running a couple Rifts and several Vives in the house now - 1070 to 1080 I see NO difference in AH performance, you'll be MORE than good to go with that card and a Rift.
Also - get the Rift. Hands down. For now anyway. Far more along for cockpit games than the Vive is, HT/Skuzzy have both said their drivers and software are way better for them to work with, more advanced, etc than the Vive. This shows in other flight sims too if you're into any of them. There is only a single game I keep my Vive for right now, it's more of a..."non sim gamer" experience IMO - not that it's bad, it's truly fantastic and the controllers are incredible, it's just for more non-sim gamers is all. There is a new FPS/Combat game called Onward that is Vive only, and it's beats, if it didn't exist I'd never touch our Vives and just let the nephews and nieces take them home.
Waiting isn't a terrible option right now, you are missing out on a lot of the "new" fun and experience, however there are a couple things waiting in the wings which may make waiting a wise choice if you aren't in a major rush. Razor has a OSVR2 set coming out very soon, cheaper by a couple hundred dollars at least, open source so it should work with all Rift/Vive games (I think, AckAck knows more about this), be cheaper and easier to upgrade to 4k when that comes, plus will be open to any of the new open source controllers being made by the dozens right now. I'm getting one at least when they come out. They also have a in headset focus thing so you won't need your glasses apparently either.
VR is the future for sim gaming - once any player tries it they'll see how evident that is. It's great now, and it's very early days, yet HTC has already made it feel very polished and incredible. In a couple/few years once the 4k and better headsets come along, better drivers/software, and above all ideas from HT/etc on how to implement all that - it'll be must have. It comes down to where you want to get on the ride is all - if you can at all swing it, I would, right now. Even if it means dropping another hobby, you won't care, as all you'll want to do is fly in the stupid thing once you have it. I used to buy a new "gaming" 144hz or higher gaming monitor of ever increasing size and res every year, at least. They cost more than the VR sets do, and a single Rift has put an end to that monitor arms race for me, as I play mostly sims/games that support the Rift. If you consider it that way, a 600 dollar Rift isn't a bad deal right now.
There are also a number of guys here that can help you out with it, FLS, others, Vulcan especially who has been posting about VR for years, and now finally others have caught up with him and given him some company. Every question/issue I've had so far has been answered by either another VR player or actioned by HTC already.
