I really enjoyed it, and still like it after about 3 viewings. It contains no essential information, and the stories for the most part are throw away, but it was entertaining.
Origins was interesting, and you see the Forerunners at their prime for what I think is the first time. Odd One Out is hilarious. The Duel is a pretty typical samurai story through an Elite filter with a really unique art style and goes into explaining the history of the Arbiter ranking within the Covenant. Homecoming, despite what seems to be the general consensus, was the only one I didn't like.
I'd say go for it, if you love the Halo universe you shouldn't be disappointed. Expect good not great, and it makes for a good two hours.