Sometimes a QTE can be interesting or implemented well, say like a Naruto Shippuden Ultimate Ninja Storm title, the QTE's in boss battles for those are actually quite nice... but then you have QTE's in the Resident Evil games, 5 and 6 particularly, which I call torture at about 3 o'clock in the morning, and way overdone. Still, it doesn't change the fact that I love Resident Evil 6, and it's my favourite out of the series that I've played, aside from 4 (I haven't played 4 in a while), and like most people, I consider Leon's campaign to be the highlight of the entire game.
I think the biggest gripe most people have with it is that it's hard to classify it under survival horror anymore, and yes, if you do try to label 6 a survival horror, you're likely to be bound for disappointment, but if you just go into the game without expectations, you may be pleasantly surprised; that said, it also does well at continuing the overall plot of the series, despite how somewhat convoluted it has become, so that makes it fine in my books no matter what.