So background, I've been flying aircraft since 1968, and sims (military and PC) a lot, with and without visual/motion/control loaders and now VR and FFB. IMO, VR is the biggest improvement - flying on a flat screen is a nice game, but still a game; VR makes it a simulation. It's not only depth perception, it's the one-to-one correlation to where you are looking as well as the presense of parallax which makes a huge difference. VR is better than the best military dome sim, and I've worked on the best; which is why militaries are going VR also.