TidBITS:

There’s no question that the App Store has had a significant impact on individuals and developers alike…The App Store’s numbers are also hugely impressive. Over 500 million people from 155 countries visit the App Store each week, and Apple says it has paid out $100 billion to developers over the past decade.

So yes, the App Store has been successful. But it’s a just a store, and one that suffers from poor app discovery and high developer transaction fees. And how much of its success is due purely to the popularity of the iPhone and iPad?

Engst does a good job of looking at the pros and cons of the App Store.