I've just signed up for Impulse yesterday, and I've already bought five or six games because well, it's just so good! I prefer this place to Steam though I feel that the Friends list features on Impulse is horrible and doesn't work as well as it does on Steam, Whatever.
I bought a few games I've had my eye on, such as Demigod, Political Machine 2008, Sins+Entrenchment, World of Goo and Titan Quest Gold. I could have bought two titles I've just listed on Steam, but seeing as Impulse looks nice, I decided to just buy them here.