It's so hard to rank the Halo's for me, they were all great to me and bring back memories of different years in my life. I'd have to say Reach is the worst (though I still enjoyed it) and 4's campaign is the most polished but I just dont know
I need to invest more time with the game before I can make that call honestly. I love the game so far and find it very addicting. I'm just really on the fence about all of the CoD-inspired elements. I do love Killcams though.