Apple iTunes vs. Google play
Which is better
Google Play fucuses more on app, and games. while iTunes focuses and makes most of its revenue on music. Google play is mostly used on mobile devices while iTunes is used more often on a computer. iTunes is also a program rather than a website.
Both Google Play and iTunes price points are mostly focused on free apps, generating revenue from banner adds throughout their app.
The layout is practically the same for both Google Play and iTunes, both have a top free apps list and top paid apps list. For the overall layout its pretty much the same and differences are miniscule.
For which is easier both of them are straight to the point and some say one copied the other, but I wouldn't say one is significantly easier then the other one.
There is a small list to which apps aren't on the Google Play store but nothing to declare this store is missing a giant chuck that the app store has.
Which Has More Apps
Both have a app milestone of 700,000 apps in thier store as of summer 2012.
Google has an easier process then apple because you can wright the code on any kind of computer where as apple has you write the code on an apple computer. You can buy the cheapest crappiest computer ever and you'll still be able to make an app on Google Play store, the cheapest apple computer is still one thousand dollars.