Steam has a fair amount of suspicious games. Nowhere near the amount as the App Store since Steam isn't a self-publishing platform, you have to sign agreements with them and get an account rep and stuff.

Steam excels because it does a far better job than than the App Store of making sure that quality is always on the front page, while also making sure that the front page changes often. I think they have found a good meeting point between content/metrics-driven decisions and an editorial voice for picking what gets featured. The App Store, not so much.