Odd that you have a problem with the Netflix app. That's something I didn't experience with my TV. I did have the latest firmware, though. Maybe that's why? Good thing you have the 360 though!
Yes, Vizio support tried really hard, and said that they thought game mode should be selectable in 3D mode. (they weren't 100% sure! lol) The gent I was on the phone with said he would call me back the next day after an employee there with the same model TV (they didn't have a PS3 there to test it with, which is what I was using) tried his at home. He never called back, but I felt we had tried everything we possibly could short of a firmware update to fix it. Basically they thought it was an issue with using the PS3 with the TV. Your post dispels that theory.
So I took it back and tried my luck with a Samsung Plasma. It has even worse issues! Buzzing, screen flashing in bright scenes, and horrible crosstalk in 3D - despite reviews saying it had very little!! I feel like aside from black levels (the Samsung is superior in this one category) and TV size (51" Samsung), the Vizio was just the better TV. No buzzing sound, no flashing screen, very little 3D crosstalk, and great picture quality.
So, that's where I'm at right now. I'm returning this Samsung now as well. I don't know what to do after that. I'd love to have the Vizio, but I really want to play games in 3D. Someone help us out!