HTC's One smartphone definitely looks like a winner, but there are always things that can push a prospective buyer over the edge, to the point of pulling their wallet out and buying it.
A simple Google+ post from Koushik Dutta, who works with ClockworkMod, used the HTCDev unlock on his One smartphone, where he says some magic words about it: "Uh. So, I wasn't expecting this, but the HTCDev unlock on this device actually behaves properly, unlike its predecessors. It behaves like a Nexus device".
So there you have it, an unlocked HTC One is pretty much a Nexus device. This is something I've asked about for a very long time - why don't smartphone makers give us the ability to roll back to stock Android? It looks like HTC's One might just be that little bit better than the competition in that regard.