From a technical standpoint, HTC has had shyttily built phones over the years. The Sensation is the worst built phone i've ever seen in my life. Just a buggy piece of crap device. The Evo was pretty rough too. Lots of mic problems and connector issues(poor factory soldering) and because of that, the mics would go bad because they're right next to each other on the board. LCD issues on that model as well. Another common thing i've seen over the years too is crappy SD card slots
Thats all from a hardware perspective..which im sure some folks will come in here and

saying "bu bu bu bu Samsung is plastic" which is really a preference, and not so much a build quality thing.
I work in the industry btw if you're wondering.