The problem is that artists like Skrillex and Rusko have become so insanely popular in the last few years that their names have become synonymous with "dubstep", when they're really not true to the roots of the genre at all. It's more accurate to call Skrillex something like glitchstep and Rusko something like bro-step (due to the insane number of tanktop wearing, YOLO spouting bros you can find at his shows). The entire "WUBWUBWUBWUB" sub-division that is so popular now can be attributed in large part to Rusko. Listen to a song like Woo Boost and you'll see what I mean.

Now, that's not to say that I don't like that kind of music. I actually really enjoy both Skrillex and Rusko, but I don't like it when people say they don't like dubstep because they hate Skrillex or some similar artist.

Cuch is right that the old guys are some of the best, but there are still some new guys kicking it hard out there (To get a taste for the classics search for any of the Mary Anne Hobbs hour-long mixes, she was key in bringing dubstep to the masses). The problem is that they're overshadowed by the brostep of Skrillex and Rusko.

Examples include:

XXYYXX
Plastician
12th Planet (not exactly new but still massive and still performing)
Kode9 (again, kind of old-school but still releasing new stuff)
Burial
The Widdler
Phaeleh