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Pro Native Windows support
It offers the best integration, ease of use and support with Ultimate and Enterprise editions of Microsoft's Windows Vista and Windows 7, and with the Pro and Enterprise editions of Windows 8.
Pro Volume-based encryption
BitLocker allows encrypting an entire volume including the OS.
Pro Multiple authentication methods
You can use a combination of methods consisting of Trusted Platform Module, PIN, and a passphrase on a USB thumb stick.
No public audits possible.
Microsoft could want or be legally required to puts backdoors without users knowledge.