The tops of Superman's boots are slightly different

Depending on the viewer, some fans have said that the blue looks somewhat lighter and more blue, rather than navy black. That may be true, or it may simply be the lens the photo was taken with.
Remember, also, that depending on the promo shot for Man of Steel, the background for the "S" shield could be very different at different times.
The tops of Superman's boots are slightly different, with a more layered look. This may be a minor tweak to look more like the comics, where there is a clear double line. They had something like it in Man of Steel but the line/seam/whatever was so narrow that it almost looked like just a very thick seam rather than a design unto itself.
The "V" in the middle also goes down less; it looks (again) a bit more like it does in most depictions in the comics, versus the more swashbuckler-type look of the Man of Steel boots.
which is still somewhat larger than its most common presentation in the comics.
This one will have to be mentioned hand-in-hand with the logo: the colors seem to be richer and have more contrast in the new costume, particularly the yellow in the background of the Houe of El shield.