I thought that this was a really good expansion for the early to mid game although I found Exalt to be a bit weak. I was hoping for more from them but found that they are too easily exploited on levels where they have objectives. I was lucky that they only stole my money (very little) and not research, I can see how loosing reaserch to them would be a serious kick in the bollocks. Over all though it is really enjoyable. However, the end game remains largely unchanged which is a bit of a bummer. As I usually either am wiped out by the end of the early game or am steam rolling them after the mid game with the endgame being fairly easy.
Does anyone think that they are going to do another expansion to enhance the end game? I ended up doing all three base attacks over the course of a couple of ingame weeks which was excellent and really thrilling as I ended up fielding my C team mostly due injuries. After that though, the challenge was much less.