Why does it matter if a game is exclusive to Windows Phone? Although I've seen some Xbox games available on the platform.
Maybe it's just the Lumia, but if games are not the central reason to have a phone, Windows Phone is just fine. Messaging is a breeze, and from their app store, I downloaded a bunch of simple apps that are genuinely useful - like using OneNote for shopping lists (I don't touch OneNote on a PC and had no idea what it was for, until I had the phone). In my experience, the typing experience on a Lumia 520 is a lot smoother than that on either an Android or iPhone. I've found myself using the phone a lot more than I used to use previous phones
If games are important, however, then iPhone or Android is the way to go