Kits have different models, American or other. Not every kit is bad, i have purchased many times kits that are actually very slightly used (mainly for checking) and not refurbished.
The older 2013/2014 kits are awful to buy, latest ones can be purchased after thorough checking.
Yeah, that's in home capacitive key. It's not a button actually, because at first i was like, the button is stuck, poor HTC and then i realised it's capacitive. Lol.
HTC has awesome sound quality and output, so if you are an audiophile, then HTC or LG V series is your best bet.