I Love impulse more than steam. Steam just feels like its draining your pc resources away from you, impulse I rarely notice. Another thing I hate is when I am on the start screen of empire total war, in the corner of the screen it says, (New content avlaiable, press here to purchase)!?!?!?!?!, it just annoys me when they advertise stuff like that, if I want more units or an expansion pack for the game I WILL BLOODY FIND IT MYSELF!
last time I heard the CEO of stardock was outsmarted by a mouse, unless the owner of steam is a mouse, I think it is safe to say that impulse will go a long way. 

Frogboy Vs Mouse
Until impulse gets games like empire TW, Nepolanic wars, Half-Life (- Very unlikely due to steam being owned by valve, and valve created half life) and games like modern warfare 2, its likely growth at stardock will continue to increase, but by having these games, it could have grown more rapadly and would have created a better brand awareness which = more customers