HTC One is better than Xperia Z. The extraordinary features of this device is able to give great competition to iPhone 5, Blackberry Z10 and Sony Xperia Z.
You didn't specify what HTC, for all I know you could be referring to the G1.
But if you're talking about the One, which seems to be the general consensus here, then yes it would be the superior buy.
HTC smartphones are much better.
Recently i have bought HTC butterfly S, one of the most impressive and interesting feature of HTC Butterfly S is its camera. The device sports a 4 ultra pixel rear camera with Flash LED along with 2.1MP front camera.