I bought a G2 a few years back, flew it every day for seven or eight months. The largest benefit that I have found is airplane orientation and control. I practiced until stick manipulation was second nature. In my opinion, sure makes it a lot easier to learn to fly the real thing when you don't have to think about where to put the sticks to make the airplane do what you want. The one thing that I didn't think about is at the flying field you are standing, and flying the simulator you are sitting. For the first few flights expect your knees to shake like hell for a while, it will pass with experience.
-Tom