I love 0 A.D.! The only issue I have ran into is it slows down so much that it is basically unplayable with more than 4 players or so (or a few AI players). I've been meaning to jump in for awhile and help improve things.
[1] http://trac.wildfiregames.com/ticket/1756 [2] http://trac.wildfiregames.com/ticket/1942
Is the multiplayer turn length still really long? (500ms IIRC)