"The only commercial support worth having is for the case when the encryption key is lost/forgotten and they can use their backdoor to decrypt your data for you."
There isn't a backdoor in commercial / recommended settings installs of BitLocker, unless by choice you create a recovery key - in which case you normally store it in Active Directory.
The support certainly is worth having - we received excellent support in recovering encrypted data from a corrupted disk (we had the recovery key).
For home users though, there is a back door in that your recovery key is by default backed up to One Drive, so potentially other parties could access it. Simple to delete it if you are aware of this and care though...
Biting the hand that feeds IT
