It’s been quite many years since Blackberry Technology has rule the world with its impeccable, secure and fast messaging technology on mobile devices. Now the industry has changed, with the introduction Microsoft Exchange Server 2007 it seems to me that monopoly of blackberry is over. I have seen several projects where Clients are moving from Blackberry to Windows Mobile services. The BIG question WHY? Simple cost and TCO. Below I am going to discuss the same where I will point out the comparison between both of them.