Over the past year or so, HTC devices have become notoriously more difficult to root/mod/S-Off than the devices of yesteryear. When one series of devices gets cracked, the next generation released by HTC has historically been drastically more difficult to crack.
This has been the case for some of the more recent HTC devices; namely the Amaze, Rezound, Sensation/XE, Vivid/Raider/Velocity, And MyTouch 4G Slide. Up until now, a few of those devices have never even received S-Off status. Now, though, thanks to a new method called JuopunutBear by the Unlimited Team, all of the aforementioned phones can become S-Off.