I have sunk several hours of my life into Civ5 (and played very few multiplayer games).
The thing about the series is that I can sit, build a large empire and take my time. In every non-turn based game (AOE) etc, everyone rushkills and shoots for metrics like FC (fastest castle) etc. without building a lasting empire. The civ series allows me to truly enjoy this aspect of the game.
OTOH, in Civ5 I have found the battles sorely lacking (the AI is not clever and artillery can do some very solid damage) so I feel cheated a bit. I still haven't found a game that combines the elements of Civ5 I like and also demands a good battle strategy.
This one Reddit post will probably waste thousands of what could be productive hours... I am sorely tempted to play Civ3 or GalCivII:TotA today.