Bitlocker has its good points, mainly that its included in Windows and it encrypts an entire drive, regardless of the type of drive or its location (internal or external) in the system. Bitlocker also works with TPM keys and chips to add a hardware component to the encryption.
Room for Improvement:
Any software encryption will take up additional space on your hard drive or storage device, and Bitlocker is no exception. Also, Bitlocker is only available on Windows 7 Ultimate and Enterprise editions, not Professional which most small and medium business users use.
From my own personal experience, Bitlocker is one of the easier ways to encrypt a drive. The inclusion of TPM and hardware support is a definite plus, as it allows it to work with smart cards and PIV cards from a government perspective.