As someone who never, ever got the hype over Halo (yes I did play the multiplayer yadda yadda) (sorry donnie) i've really enjoyed this so far.
The combat is where it really shines, it's just so wonderfully satisfying and never feels clunky.
Not sure how much will be below the surface once i've digged a little deeper into the gameplay, but as sheer shooting entertainment goes it's not too shabby at all.
There are elements of it that reminded me of Warframe - but as you rightly guessed, the gunplay in Warframe is nowhere near as good.