It's not bad, the majority of the complaints are from anime fans and as they can be ridiculous in their fandom shouldn't be taken too seriously for the most part.
Anyways the character animation/artwork could be better as it has inconsistencies. It's alright in some parts and kind of poor in others. Also sound quality in the voices could be better, not so much the voice work as much as the sound qualiy. Armin is fine as he's clear, Mikasa & Erin aren't.