Depending on how much getting an unlocked bootloader is worth to you, you might want to read this thread - Verizon HTC One General - Purchased a JavaCard for S-OFF
Among the many things you can do with S-Off you can use the Super CID tool, which allows you to enter working information into the htcdev site, you will not get the error code when trying to your identifier token.
What is being offered is for Sonic2756 to use a HTC developer tool called a javacard to get S-Off for the Verizon HTC One and a number of other HTC devices.
I personally think this is a great deal, less then $50 after all the shipping/insurance expenses get added in, for someone to use an official htc method to get s-off. Even though the chances are good that someone will find an exploit to achieve s-off, the chances are also good that an exploit like that will take a while to develop and those exploits could run the risk of breaking your phone and giving you a fancy paper weight. I believe using a HTC developer method of achieving S-Off to be the safest way to go, provided you dont cut corners with packaging your phone and ship with insurance for it.