The main difference between the Android market and the Apple store is that Apple decide what is allowed into the store, and what isn't. The major benefit of Google's approach is that anyone can submit their application to the masses, keeping in tradition with the open source way of life.
However, the downside to this approach is that anyone with half an idea of how to construct a few lines of code can enter their idea of what an application is. The result being, the marketplace is full of half baked ideas, untested software and kids rating 5 stars saying "first" before they have even looked at the software. Conversely, there is a fair amount of *very* good applications out there that are being developed with freedom in mind.
Now consider the "paid apps" that will be introduced into the marketplace, no one is going to part their hard earned cash for some third rate application. If Google have any sense (and I am a firm believer that they have more sense than their competitors) then they will follow Apple's lead and filter out the bad apps from the paid market and offer the developers to keep it in what is currently the "free" market.
This would result in two independent markets, one like we have now with free applications that anyone can submit to, and another market where the apps warrant a contribution from the community with respect to a few pounds/dollars/yen/yadda yadda yadda. This would also stop(limit) the moronic youth from downloading just to yell "first".
I hope this is the way the market will eventually work, if not then it will fail. Downloading rubbish you have to pay for will give Android a BAD name.