1. Windows 7 Mobile
1.1. Pros:
1.1.1. The operating system also provides access to SharePoint-based documents.
1.1.2. Microsoft produces an excellent productivity suite in the form of Microsoft Office.
1.2. Cons:
1.2.1. Windows Phone 7 doesn’t support the full range of Exchange ActiveSync policies
1.2.2. Lack of support for removable storage
2. Hardware
2.1. Processor
3. iOS/ iPhone
3.1. Pros:
3.1.1. now allowing certain apps to run in the background.
3.1.2. You will now have the ability to add custom wallpapers to your springboard.
3.2. Cons:
3.2.1. There is no jailbreak or unlock for iOS 4 yet
3.2.2. Most of the new features of iOS 4 can be replicated or even improved by jailbreak apps
4. Android
4.1. Pros:
4.1.1. The ability to overclock the processor
4.1.2. Backing up all the data and apps on the device;
4.2. Cons:
4.2.1. difficult to find accessories for your particular phone model.
4.2.2. Some models have limited processing speeds, which can make for delays.