I really enjoy the Single Player. I'm undecided on so much being tied to a civilization's "happiness". Seems in any game where I expand it's always, "ok build the next happy building in the city".
EXTREMELY DISAPPOINTED in Multiplayer. I played a lot of lengthy 10 human player games in Civ4BTS that would last a few hours and be tons of fun. Can't even play stable 4 player Multiplayer game of Civ5. And Steam's lobby system SUCKS.
Guess I can just hope it gets fixed.