I finally got a chance to sit down and play it a bit. The changes are really great! I love the fact that it puts your chosen banner on the shields now, not to mention some of the surcoats. Lots of new heroes to hire, and you can capture enemy lords or choose to let them go. Various graphical improvements, more detail for the characters, and more...
Unfortunately it's also less stable. I've had it lock up a couple of times. At other times there are random temporary freezes, even in the map view.