Cool riffing! Good tone.
I liked it.
My only criticism would be wholly subjective: the tone was a little dry. Good, overall, but were I personally to choose to make it better in any way it would be to add some high end. Its got the chug and growl (which it sounds like you've gone for as a big part of the tone!) but the higher section of the riff doesnt cut like it sounds like it wants to (maybe a little compression to bring that out?). Just my taste, though, feel free to ignore.
Otherwise, nice mix. Good drum sound, too!