On nightcore:
I don't like their stuff.
True there are a couple of remixes that have been really definitive, but most of their work just feels... lazy.
There's this really intense sense that someone made this remix, listened to it, and decided to publish it even though they knew it wasn't good enough.
Yeah, yeah, they've produced thousands of songs or whatever, but quantity is not quality, and up-pitching a song and adding a (literally!) one-note sub-bass channel is not quality.
They really remind me of the Dub-step I was exposed to before I was exposed to any good Dub-step. I almost never got into Dub-step because so much of it is so bad, and that would have made me miss out on something I really enjoy.