Always sell things the easiest way for everything to be done universally. For example, if you keep S-Off the person buying it in the end can easily place the Sec Flag back to on even without root, relock OR keep it unlocked, I am not picky about Sec Flag but bootloader being unlocked I am. So might as well keep S-Off because it isn't going to take away the ability to root or accept an OTA but WILL give the End User the ability to downgrade if they do root 4.3 and wants to go back to unrooted properly. S-Off and Unlocked will both still get OTAs easily. No matter what you do, go ahead and run the RUU to bring it back to bone stock abd accept all OTAs to get to 4.3 for them then do an FDR and give it to them with S-Off so they can downgrade if they want to.
Sprint HTC One(Unrooted)
Upgraded From Sprint Galaxy SIII, HTC EVO 4G LTE and Google Nexus 4 16GB(Unlocked)