Pros: +Fun and deep gameplay, lots of viable strategies and playstyles makes the game very accessible.
+The game is pretty easy to mod, and theres a huge, still living mod community.
+Mods are WAY better than Civ V mods, most mods are huge overhauls that add sci-fi elements, fantasy elements, make the game more "realistic", it's just great.
+Good variety of Civs, each with two traits, two uniques and two starting techs.
-"Native America" is a Civ, which is really dumb, the leader is Sitting Bull, a chieftain of the Hunkpapa Lakota, his unique unit is a Dog Soldier..a soldier class of the Cheyenne and his building is a Totem pole....which is a religious symbol for Alaskan (I forget which) tribes.
-The "health" system seems like an unneeded secondary lock on how big cities can grow.
-The "happiness" system is generally good, but can lead to some annoying moments.
-Traits aren't all that balanced, "financial" is just so good while "protective" is just so bad.
Quite possibly one of the best games I've ever played. Games are long and difficult, leaders are very animated and expressive and the soundtrack is utterly fantastic (Netherlands and Greeces theme are such smoothing tracks). The leader variety is slightly greater than Civ V (but Civ V has more civs with more unique abilities), and each leader has two traits, like Abraham Lincoln is Philosophical and Charismatic while Montezuma is Aggressive and Spiritual, for the most part these traits are fairly balanced, but there are a few expeditions of just play bad traits (Protective is infamously underpowered).
Each Civ also has their two "uniques", unique units and unique buildings, unfortunately I don't really see these often being huge game changers with a few expeditions like Englands Redcoats, Ethipoias Omoro Warriors or Sumerians Ziggurats, this is probably cause the games combat is by far the worse aspect of it, units stack meaning most depth and strategy can be replaced with simply rushing enemies with strong melee units and hope to win, hope you built a lot of archers!