I'm generally not a big fan of strategy games with asymmetric gameplay, but this series has long fascinated me, at least on a conceptual level.
The asymmetric gameplay is its greatest feature in my opinion (as it was with the first game). It makes the game more strategic in some ways, forcing you to pick your moves a lot more carefully than in a lot of games. The idea of trying not to rouse a sleeping giant has always appealed to me.
I've actually only played one campaign all the way through - the reason being the game has been getting, and continues to get, constant massive updates, as you say. I know I won't complete a game before the next one drops and I don't like that in any game. However you might have inspired me to get it installed again...
But anyway, yeah, big fan here. I basically buy everything Chris puts out but the AI War series was always his magnum opus. I rate The Last Federation very highly too.