I purchased this the other day (£30 at Sainsburys - bargain, I thought) and lo, my weekend summarily disappeared. They've certainly worked out some kinks of the old one and it seems a much better experience. The graphics are better, the gameplay is smoother, Ezio has more flamboyant methods to kill people and, by the looks of things, they've balanced out the earnings scale (a little).
Now all I need to do is find ways to convince various people to get off the Xbox, so I can get back into 16th century Rome.