The only thing that affects how long it takes to brute force a password is length and entropy (the different types of characters used). Passphrase is designed to make it easier for a human to remember, so if you are using a PM to remember it anyway, a 64 character random password is going to be better than a 64 character passphrase.
I usually use the password generator in the 32 character range with all of the symbols, numbers, and characters included, since it seems like a lot of places don't like longer passwords.