I stopped playing after about a week and keep meaning to go back and play it some more. Great concept but sometimes in the mechanics annoyed me.
It's definatly got a learning curve. If you are new everything takes dozens of minutes to build, but once you learn how everything works things get rolling. I rarely play game that last longer than 40 minutes, and in that time I make armies, expermental units, build shields to defend from artillery, etc...
Although this is with FA. FA is what SupCom SHOULD have been. It's much much better gameplay+balance wise and all that. But even with normal SupCom the above was possible, just with a different more "turtley" economy (you just spam mass fabricators).