Gotta be Nile just because they have the greatest quantity of awesome stuff. Necrophagist is close, but Noctambulant is the best album by any of these bands.
I said Spawn of Possession. Second choice would be Necrophagist. Then Anata. I'd put Gorguts in front of all of them, but I just don't consider them a tech death band.
I don't think Hour of Penance, Nile, and Fleshgod Apocalypse belong on that list. Awesome bands, all highly demanding instrumentally, but not tech death. There's also a serious lack of Odious Mortem there.
The line between tech death and brutal death is so paper thin. I can't decide between that group lineup. And there are too many other candidates I would have put, like Coprofago, Pitbulls in the Nursery, Lykathea Aflame, Origin, Non-Human Level, Quo Vadis, Illogicist, Cryptopsy, Neuraxis, Amoral...oh fuck, there's too many.
That must be a "new" feature, it wasn't all that long ago that you could easily have 20 choices in a poll.