Except Impulse::Reactor has the same features, and it doesn't require an unnecissary app running in the background.
Except my friends are on Steam, not Impulse, and running an app in the background doesn't worry me and I'm not sure why it should.
Considering the size of my steam library, and the fact that when I try to buy Dragon Age on Impulse it tells me "Sorry, this item is not available in your region.", it isn't exactly worth making the switch. And I don't need to anyway, because I'm assuming I can run both at the same time...