I've seen 3D movies in all types and I can tell you it breaks down like this:
IMAX (true imax that is) has unparalleled sound and scope - best way for seeing it the first time. The projector in true imax isn't digital so there is some very slight ghosting in intense scenes, in this print of the film I found it barely noticable. Most comfortable glasses out of all of them (despite being the cheapest).
LieMAX (fake imax, digital projector) - Sound is much better than Real D, Image fidelity I found to be better than Real D and obviously true IMAX. The glasses are bulkier than Real D, but are also much taller in the frame.
Real D have slightly more comfortable glasses than LieMAX, but fails to recreate the same sound quality. I didn't find the digital projection at Real D as good as LieMAX, but it was still crisp (and better than true IMAX). Screens can vary in size, yet are never bigger than LieMAX to my knowledge).
Dolby 3D is the shittiest of the bunch.
I have no experience with 'Xpand 3D', but from what I've heard from people in this thread it sounds average.
Will post this in the OP.