When I look for an app, I go to the Marketplace. Maybe Google's openness is lost on me here, but I didn't even know there were third-party app dealers for Android. Getjar? Never heard of it. Of course, the only third-party app I ever installed was Swype, and I only heard of that after multiple articles on various websites.
When releasing a Free game, why not use the Marketplace? Its not like Google can take a cut of $0. And who on an Android phone is going to think "hey, I wonder if they offer a Symbian version of this app"? Multiple websites? Ever heard of auto-detect and redirect? When I go to redbox.com, they point me to their Android-friendly website.