I'm actually in the middle of completing Mafia 2 right now. Unfortunately my PC broke down(QQ) so I'll have to wait a couple of days before being able to play it again, when my graphics card arrive.
Anyway, so far I really like it, as you mentioned, the storyline is very tight, though some of the plot twists aren't all that hard to spot, at least for me. Now, having said that, it did bug me a little that you had a lot less freedom than the original Mafia. As Yathzee rightly pointed out, the game doesn't seem to like it, when you veer off course and do something else inbetween missions. You're constantly being reminded "Go home to complete mission" instead of just letting you be for a time. Some people might like that, being guided all the way, but I preferred the way it was handled in the original Mafia.
Graphics really are spectacular in this game, especially facial animations as you mention. The only real thing I could think of that would improve the game would be the inclusion of Digital Molecular Matter, like in The Force Unleashed to have the different kind of materials, including the cars break in a little more realistic manner. That's a minor thing though, and nothing against the game at all.
Anyway, those are my thoughts on the matter, great review and I agree with Lost In The Void, some pictures would be nice to space out the text.