Have a look AppShopper.com. Their 'About' statement says,
“AppShopper is one of the largest iPhone, iPad, and Mac app directories attracting hundreds of thousands of unique visitors per month with millions of page views to the site. Our audience is interested in app discovery.”
It’s exclusively iOS and Mac apps. You can register, if desired, but not doing so does not seem to limit searching. The advertising seems minimal and non-intrusive.
The Chartbeat sidebar graphic claims 335,291 apps in the Appstore. Their Appstore, I presume, the almost identical spelling with Apple’s App Store is a bit confusing.
Also confusing is an alert banner stating that a certain app has been removed from the App Store (I presume this time they mean Apple’s per the spelling.?) The oldest app in the Graphic & Design category is one such app. SketchMee was introduced in Jan 2011. The App Activity sidebar relays this app’s version progress, pricing fluctuation and other expected details. However, clicking the ‘Buy’ button brings up the Mac App Store preview in iTunes followed quickly with the App Store app opening to that app’s page on your Mac. So the app then has not been removed from the App Store. Also, just searching the App Store produced the app's App Store page for purchase. So I do not know why the alert banner says it has been removed or what it is referring to. (?)
Despite this, it is a nice app-searching alternative to the App Store.
This should give you the general flavor it.