It's an okay sci-fi show if you disregard the halo source material and act like master chief hasn't appeared in any media before. However, there is a LOT of source material to draw from and that should be used by a studio, rather than disregarding all the lore to make some D rate show for a quick buck.
There are some awkward (and downright bad) visuals throughout the show. There's an annoying subplot about Kwan (frick her and her bad haircut) that constantly detracts from the important characters. The writers also probably just glanced at a halo cover and called it good as far as story and world accuracy goes.
TLDR: only watch if you're super bored. Don't expect this series to do any justice, or even come close, to the great books and video games we all know and love.