Best Operating System

[The Legendary]

This is ment to be a comparison between the big 3 players in the smartphone market, iOS4, BBOS6 and . I want to know which OS people think is best. Please post your breakdown of why that is the winning OS. (I know that this will be biased because this is crackberry not androidcentral or TiPB)
Please break down under the following categories:
Messaging:
Applications:
UI:
Functionality:
Security:

[Gitpicker51]

Look at the new Windows 7 Mobile...just saw a YouTube video from Engadget that shows it running circles around BBOS6.

[The Legendary]

I'm not looking to buy. I'm looking to compair OSs and this convo wasn't really ment to talk about WinMo7. I was talking more about android, iOS4 and BB6 and how they all compair. WinMo7 doesn't really have anything innovative to overtake over the smartphone market. Apple has Apps (Why build anything into the phone there is an app for that), Blackberry has Messaging and Battery life (a bit of hardware and software), and android has the spot below apple when it comes to apps, but they have some killer apps that make it better than an iPhone (Swype). I'm not all the familiar with the extent of the OS though and want to get some opinions of those who have tried the device.