I can't speak for anyone else, but the reason that I can't use it is the lack of OS support:
Supported Operating Systems
• Windows XP (x86) with Service Pack 3 - all editions except Starter Edition
• Windows Vista (x86 & x64) with Service Pack 1 - all editions except Starter Edition
• Windows 7 (x86 and x64)
• Windows Server 2003 (x86 & x64) with Service Pack 2
• Windows Server 2003 R2 (x86 and x64)
• Windows Server 2008 (x86 and x64) with Service Pack 2
• Windows Server 2008 R2 (x64)
When OS X or Linux is supported, I'll have a look.