With the unlocked bootloader you can change roms and remove apps ,but can not change radios. With S-off you can change or remove almost anything including radios.

 

What does changing the radio actually do? What can be the benefits?

Also if I use that htcdev to unlock my phone does vzw really find out? If you unroot and remove everything there should be no problem?

Next question whats the easiest way to unroot?

 

Eventually, there will be radio updates for the phone. Everything always updates.

S-ON/OFF means certain things (radios and kernels) have to have an encrypted signature to flash.

The community is already able to flash radios for other HTC phones unlocked with S-ON via HTCdev, so I think the Rezound community hasn't picked up the tricks yet.

When radio updates become available, there will be flashing instructions for them, S-ON notwithstanding.

You can already flash a new kernel for example.

At present, there is no way to unroot the Rezound (unless it's come out while I've typed this, things are moving along nice and fast ).

Edit - happy to admit that I was wrong on the last bit. See Mr Smith's advice in how to unroot thread.