Several hours of my life - GONE!
This expansion has better graphics than previous releases (but those don't make or break games), it has distinct races with distinct tech trees - which is awesome (e.g. the Drengin build 'slave pits' rather than factories!), smarter AI, ehanced customizability of ships, and some minor tweaks, but other than that, it stays true to the GalCiv brand that is the standard for space-centered, turn-based strategy games. All in all, TOTA adds real value - I ordered mine in the pre-order but at $20-40 you simply can't beat the bargain.
I rate this a 9/10 mostly for gameplay - it's not a 10/10 b/c it is not particularly original nor 'next-gen'. That said, if you are a PC gamer, there is simply no reason not to own this game. It says a lot about the current state of gaming that this game (or series) isn't flying off the shelves in record numbers.
WARNING - if you play this game, you will lose several hours of your life for the elusive 'one-last turn'. I think about this game at work and hurry home to play it. I'm playing my second game, on higher difficulty, on immense galaxy, with a different race and it's like I'm playing a totally different game!