I think tar nailed it. This isn't your normal RTS. Clicking fast and hoping for the best isn't going too work(often anyway).
This is more like chess, a thinking game. I love the PBEM battles, so I can take my time, look at the board, plot my moves, all without boring my opponent to death!
I'm sure in combat commanders didn't get a half hour and 20 replays of the turn to make their decisions but this is just a game, right? I still get my butt kicked even with all my micro-managing but I love playing it this way.
So give it a chance, man. This game will kick you right in the a$$, it's so good!