Don't buy now.
Wait at least six months. I mean both wait and 6 months. The game can still be awesome 6 monts from now, really. Stardock follows their games. It's just that, well, there's a LOT of following to do...
The guy who said the AI is good might have played on the most difficult level, but I think he jsut doesn't know how to play. I think pretending there even IS an ai in the game at this stage is purely a lie.
You pick up Procipinee (oh, yes, don't build your own sovereign, you have 50 points to do so, when some of the preset ones sometimes would require 74, and that's not even the best one - if you play MP, ask your opponent to design his own sovereign, it'll be easier to beat him). Build a city (anywhere, doesn't matter for this 'strategy'). Research bows in mundane research. Research fire giant and one attack spell (choice of fireball, and variants for air and ice, I think the earth variant has a shorter range, but you can pick it too). Pick haste too, it's good for your fire giant, as it can cast it on itself.
Now, you've won the game. This unit is stronger than anything the ai will pit against you. It may end up sending a stone giant late game, but that was the strongest I saw and I didn't try to do anything but move my sovereign, her giant and a few archers, and conquer the map with my Stack Of Doom (TM).
Tactical combats are also very very awkward. The ai is braindead there once more, but that was to be expected and can be corrected someday. However, clicking, suffering zooms and camera angle changes, and having to click again is a pain.
