[LDiCesare]

I love Civ 4 and loved galciv. Nowadays, I play Civ 4 and Dom 3 almost exclusively (with some NetHack in between).
Galciv shone with its great ai. Dom 3 ai is totally dumb in comparison.

Depending on what your friend is looking for, the game has great strengths and some weaknesses:
-Dom 3 has enormous strategic depth, far more than Civ 4 and Galciv 2.
-It's just the best mp game that I know.
-There is no turn where you just push 'end turn' or long phases of waiting to get tech X before you can start doing something. There's always something interesting to do each turn. You're not waiting one more turn because something cool will be built/happen next turn. You already had tons of cool stuff happen this turn.
-You can customize your heroes with items in a way that's much more fun than Galciv 2's ship design.
-God customisation is way way richer than your race customisation in Galciv 2 or Civ 4's traits and unique units/buildings.

However
-The ai is poor.
-Beating the ai doesn't help you much when you start playing mp.
-It takes a lot of time learning the ropes of the game.
-The user interface may repel many.

As Morkilus said, Dom 3 isn't about building stuff. There are only temples and labs, though site searching has some similarities with buildings in civ (compare a +25%gold market in civ to +gold sites for example).
Also, you have to balance the use of your mages (researching, site searching, forging, fighting), and that the scarcity of mages means you'll have to build forts and labs to get more of them, which requires some strategic thinking.