Apple has a great eco system, they have more apps, however i dont think thats the best thing about their ecosystem, its the movies, the textbooks, the lectures, podcasts etc.
They are also great at advertising.
Android is to fragmented and so open everyone side loads apps and avoids buying. Whiich stunts the ecosystem. They do not restrict the hardware meaning people have terrible experiences on under powered equpiment.
Windows has gone for a nice medium, far more choice than apple, but not totally open hardware, and people actually pay for apps. The apps are high quality now as well. But they need to grow there user base and apps. They also need to keep up with hardware. Its not good releasing hardware 6months + after android has done it. Hopefully this isn't something they've learnt with gdr3 supporting high res screens and things like snapdragon800, they need to be far more proactive on supporting new hardware.
Also plenty of films that arent on xbox movies but are on itunes. Thats the thing with apple, extremely good chance what ever you want they'll have unlike android/windows.
Would take either over apple these days, iOS is just stuck in 2009. it was a great when iOS was released, they just haven't kept up with developments in android/windows and the os is far more important than 100,000 apps i wont use.
The next few years are going to be interesting with increased competition between the three major players and amazon is doing pretty darn well.