Oh, and here's my comment on sound quality. I've used SoundMagic PL11 In-Ears before, which I'd classify as pretty cheapo headphones (around 20€ @ Amazon). The sound quality of those is very similar if not better than that of CX275s'. The only advantage of CX275s is IMHO that you get a mic and a music/call/google now control button, which actually works with Android.
Actually, there are (very subtle) indicators as to which side is which. Look closely at the inside of the rubber part, where the cable enters the earbud. And you did it wrong ;-). The mic is supposed to be on the left.
Obviously, they are just cutting down the costs by loosening quality control. Shipping perfect devices to the press was clearly part of the plan, otherwise it would be just too much of a coincidence.
My wife also received a far from perfect One. It has multiple gaps in the body and the speaker covers do not line up with the plastic. She did keep it, since it's not that bad. I would never had accepted it at that price.
For now I am staying with my One X, since I can't be bothered with the frustration of having to ship the device back to the supplier multiple times. Plus, my One X's build quality is perfect...
I never had problem with allegedly overbusy or cartoonish look of Sense. It was perfectly fine for me. Touchwiz is something I consider ridiculously cartoonish, which is why I never used a Samsung device before.
I'm not sure flatting Sense out looks much better but getting rid of the HTCish tabs at the bottom is a definite improvement. It's been overdue for years.
The task manager is also a huge leap forward compared to Sense 4+, where I rarely switch to an older task through task manager because it is so cumbersome to find it.
What is that Kid Mode? The icon looks identical to the Kid Mode app available on Play, which I find rather poor and overloaded.
Tried reflashing? I was also having boot loops after debranding and flashing MCR r2. However, it went totally well on my other Desire HD where I did exactly the same. After a wipe (from clockwork recovery) and reflash it booted properly.