I like them. I think they add to the urgency or direness of a situation that would be lost if the game was entirely "make choice, watch consequences".
That's what I see as the benefit of QTEs, if used properly. They force split second decisions that result in consequences.
Bad QTEs can exist for a multitude of reasons, though. A lot of times they don't have real consequences, and exist merely as a button pressing rhythm game of sorts like some sort of password to complete a cutscene. Or if they are overly excessive for the action being performed, like mashing a button to open a chest. It shouldn't require out-of-game work to do something that simple.
It also doesn't help if they aren't representative of the actions you're performing (i.e. Press arbitrary 3 buttons to rip out liver) I mean, it wasn't exactly the example of a great QTE, but the boss finisher in Warhammer 40k: Space Marine at least had me pressing buttons that were significant to the overall game experience to beat the crap out of him, with the punch button punching, the chainsaw button chainsawing, and the stomp button stomping. I got to choose how he died, so if I wanted to do nothing but stomp and shoot him to death, I could.
I think the easiest "good QTE" to implement is the "mash button to free yourself" that shows up in tons of games, usually when you're turned to stone or ice or something of the like. Other QTEs require actual work, which is why we get so many bad ones, because developers use it as a way to get out of doing extra work.