I want a review written covering the 4 major smart phone OS's Android IPhone Windows and Blackberry.
The review must be in english.
Must be of a good standard
At least 600 words
Possible things to cover:
Market share of each OS
The most popular known smart phone of each OS
Best features of each OS
The future of each OS with the increasing competition
Any other topic that may be relevant for a review is also welcomed.