Origin - Extremely fast, with lots of sweeps and gravity blasts. The newest release is very good.
Atheist - Unquestionable Presence is a legendary album. The drumming here is mindblowing.
Necrophagist - Pretty accessible despite complex songs. Good soloing, somewhat wanky at times.
Nile - Not always super technical, but musicianship is very strong.
Arsis - Leans towards melodeath, but has more of an edge. Crisp production.
Beneath the Massacre - Pretty derivative of other tech death bands, but with some metalcore influences thrown in.
Sleep Terror - Pretty derivative of other tech death bands, but with some random jazz sections thrown in.