We viewed it in IMAX 3D - however, you need to be aware that many of the Regal/AMC IMAX branded are not 'real' IMAX experiences. Be sure to seek out a real IMAX theater (i.e. Giant Screen) if you are going to view it in IMAX 3D.
Also take the time to watch how they made the movie, all in all lives up to a good deal of the hype.