Few days in, feels bit messy, storywise, gameplay, lacking gameplay settings, research also with limited explanation. Some buildings also aren't clear as to what they do. The tutorial was ok to start but as you're dropped into the campaign there's very little in the way of guidance what most units do and how one is advantageous over another.
Just as you get familiar with the game, after about 15 missions the campaign is over. So expect about 10hrs of play.
So far, StarCraft 2 is a better choice for RTS but you do need all the DLC's to get a proper experience which could set you back a few more dosh.