[Via Examiner, thanks Tracknod]
Update: We just heard directly from HTC about this snafu, and as it turns out, the message that Sprint Hero users are seeing is merely a mislabeling. If you're within an EV-DO Rev. A area, you'll get Rev. A speeds -- despite that fact that your phone says it's only on Rev. 0. We're also told that a future maintenance release will address the message. Check the full quote after the break.
It turns out that while the phone reads that it is operating at EV-DO Rev. 0, there is a message error in the UI that states this, even if the device is working on a Rev. A network. So, the good news is that this does not at all impact the operation of the phone – if you are in a EV-DO Rev. A coverage area, you will get Rev. A speeds. However, any future maintenance releases will address the message that users see on their phones.