I've watched one film in 3D and that was the first How to Train Your Dragon film. It was good but I wouldn't watch a lot of films in 3D really. It's one of those things that is a nice gimmick but you wouldn't like it all the time.
I've seen both 3D and 4D movies. 4D are the best and we were at Disney when we experienced it. Their goggles are the best too compared to the movie theaters because when things jump out at you it really seems that they're coming straight for you. The movie theater glasses don't always have that reaction.