Rouxenator
Dank meme lord
I disagree - the 3rd party applications are what makes a product successful - it shows that the OEM has developed a strong and useful SDK.
That is a very valid point. Having a platform for developers to work on is very important for gaining market share. However this goes hand in hand with having a complete package out of the box. Those two factors, along with being open source, is what placed Symbian at the top : http://en.wikipedia.org/wiki/Smartphone#Operating_systems