Well, after today, I've seen the movie in both formats. The film itself is wonderful, I absolutely love it. But, as for the preferred viewing format, 2D is the clear winner for me.
While watching the 2D version, I was struck by what I perceived as noticeably increased clarity, sharpness and overall detail. Certainly, I was able to take much more in, and pick up on minutiae I missed in 3D. The contrast was stronger, the colours "popped" more - and overall - the image had an elevated sense of realism and, well, depth!