Of the trailers I have seen they all look good. Mirror Mirror appears to be the only one focused towards a younger, family audience. The others are darker, but more diverse. I saw the extended trailer for Snow White and the Huntsman, and was very surprised. Charlize Theron as the Evil Queen looks very good. It may be a little too Joan of Arc’ish; but so far from the trailers I have seen it looks very good. I also watched the trailer for Jack the Giant Killer and that looks like it might be good too.
Mirror Mirror looks good, I think it will be fun to watch. The other trailer I saw from Dreamworks is Rise of the Guardians, which teams up Santa, the Easter Bunny, the Tooth Fairy, and the Sandman to fight an evil. Looks like a good year for Fairy Tales for all audiences.