The only difference I can find is that a few of the normal top menu items have been slightly rearranged. The colors and icon set are likely stock vBulletin items. I agree that the looks of it are a little mundane, but they don't hurt the eyes like some boards I've seen. The structure is identical to the previous software, so there shouldn't be much of anything to re-learn.
HD, look at the top-left under the new logo for the link to your PM's.
HD, look at the top-left under the new logo for the link to your PM's.