I really like that you can buy tiles now, it always peeved me that there was basically nothing to spend gold on in Civ 4. I like the inevitability of golden ages. The interface is nicely streamlined, it's easier to click on a city, and I like that there's a button to select research, production, etc... when you get around to it instead of being forced to make a decision. I like that cities have their own defenses, it kind of simplifies things. It's really cool that you can search the civilopedia. The social policies are alright, but feel kind of cheap like something you'd find in Civilization Revolutions. I still don't know if I like that you can have only one unit per tile, but it makes it easier to see what's going on. Hexes I think are pretty decent. I haven't played enough of the game yet, but I still fear it's lacking the depth of BTS. What do you guys think of the changes?