No one has gotten it perfect, but in terms of just a good, solid art style that is actually true to Halo, those are my picks.

Personally, I would REALLY just love it if they would not use hand-drawn art at all, and would utilize the same method that Scott Christian Sava uses in his children's comic The Dreamland Chronicles (link: http://www.thedreamlandchronicles.com/comic/page-1338/).

That way, the best assets are used, everything would be to scale, and the fidelity to the source material would be idealized. They could photoshop the end results however they wanted, just like Sava does with his work.

Imagine the comic version of the scene in Halo 4 between Chief and Del Rio, and you get an idea of what I'm imagining:

As for the WRITING, that is an entirely other story altogether. Not sure who's at fault there, the writers may just be writing what they're told to, but man, it is the worst. The WORST.

Blue Team reunion:
"Sup."
"Sup."
"Hey, you're a Lieutenant now."
"Yup."
"Neat."

And the Didact's portrayal as the union of Dr. Claw and Skeletor is just... mm.
Gotta hold my tongue.
Don't wanna get off-topic.