When things are mass produced of course you are going to get quality issues along the way. I see it every day at my work place.
Especially when the manufacturing process is a lot more complicated for a number of reasons:
- material being used (aluminium is a lot tougher to shape and work with than plastic)
- the design/shape (shaping the body of the one takes a very long time and not to mention the process in comparison to shaping plastic)
- the finish process (again a lot more complicated than just applying a glossy layer)
And another very important factor, this is a completely new design for HTC, so considering they have started from scratch with a new type of body, not only just the design/shape process but also having the antenna built into the body for the first time ever with a handheld device, I would say that they have done a pretty damn good job.
Where as with Samsung, they have used the same materials, finish, similar design/shape etc. since the GS 1 and so have had time to more or less perfect the manufacturing process etc.
Samsung even said themselves that one of the reasons they use plastic is because it is easier to work with (other reasons being, quicker to shape etc.)
It will be interesting to see how Samsung do next year when it comes to QC/"build" if they decide to use a metal uni-body.