Caught the 2D version earlier this evening as it finally made it onto a screen in Bristol, I have to say I think I preferred it to the 3D version. Don't get me wrong, having seen the 3D version 6 times and loved it, I just found the picture clearer and sharp and easier to watch. It could be because I wear glasses and have to wear the 3D ones over the top, but the 2D experience for me was a good deal more enjoyable.
Be interested to see what the opinion of other people who have seen both the 3D and 2D version is.
Overall I'd say that the 3D hasn't particularly enhanced the film, but then I don't think it has detracted from it either, which I guess makes it a bit 'meh'.