Well, mostly. The
Honeycomb Inexplicably Offset Icon Grid is still arranged in the same way, but the actual honeycomb graphics—that is, the hexagonal icon containers that filled the original matrix—have been done away with. The second most apparent change is the new scrolling behaviour, which limits flick scrolling to a page at once to prevent overshooting, which is especially useful if you take into account many WinMo phones' imprecise resistive touchscreens.
Other than an apparent (and welcome) systemwide increase in UI speed and smoothness, that's about it. If you've got Silverlight, you can watch Microsoft's whole presentation here. [Ars —Thanks, Slimy]