Rather than vote in the poll, I'd like to reply in regards to each option. Firstly, I'd like to say that I am not a fan of the Anniversary graphics as a whole due to the character models and enemy units having changes that I'm really not a fan of. However, I think the Anniversary versions of Halo 2's levels are brilliant for the most part.
The Armory / Cairo Station
I absolutely love how this level was done in Halo 2 Anniversary. Unlike CEA's Pillar of Autumn, the updated Cairo Station is almost completely faithful to the original with better textures and lighting. The only downside is that some areas are a little too dark when compared with the original.
The Anniversary versions of these levels did a great job, but I have to nitpick a bit. The atmosphere of the central island is spoiled by the change from the crimson overcast of the original to a generic blue sky. I find this change to be quite an odd decision considering half of the original Halo 2's marketing prominently featured art with the crimson sky. The other issue with these levels is the glitchy second bridge that should not exist.
The Arbiter / The Oracle
These are the first levels where the upgrades didn't feel particularly upgraded enough. They're fine. Nothing to write home about. I also would have preferred more use of the classic Forerunner tessellation patterns rather than the very basic Reach-style of Forerunner flooring. I also find the new Banshee score to be quite dull compared to the original track.
While Regret leaves a little to be desired, I absolutely love the upgrades to the ruins and flora of Delta Halo. I appreciate details like the lake towers now emitting beams of light in pulses as the structures of the original Halo did. Overall, the colours really pop, and I love that. I felt the second level of Halo CEA really wasn't up to scratch with their colours compared to the original. It looked more bland and less lush in my opinion. But here, Halo 2 Anniversary did it right.
Sacred Icon/Quarantine Zone
I really get the feeling that the Arbiter's levels did not have as much time spent on them in Halo 2 Anniversary. Once again, these levels don't feel like that much of an upgrade, and the bright, aquamarine pools in Quarantine Zone appear unfinished in the Anniversary version. Still, at least they're faithful... Aside from the lack of Flood-spores (green fog) in some areas.
Gravemind / High Charity
Now these are the levels I actually have an issue with in the Anniversary version. Instead of making the colouring and textures faithful to the original or adapting it to be faithful to Halo 3's High Charity, it went in a completely different direction and made everything a desaturated navy colour. Halo 2 had the most vibrant magentas of any Halo game, and the textures of the walls and flooring remained consistent when they appeared in Halo 3. Halo 2 Anniversary has spoiled the continuity for no particular reason other than to have the Covenant's aesthetics fall in line with something closer to what we got in Halo 4's Spartan Ops and Halo 5. The new lighting is cool (even if it spoils the mood in some areas) but other than that, I am really not a fan. The lighting on the Flood biomass is broken as well.
Uprising / Great Journey
It's funny how much the Anniversary versions of these levels resemble Halo 3's Sierra 117 and The Covenant levels. I don't have much to say about them. I like the upgrades and they're faithful. My only nitpick here is that I can no longer hear the ambience of the hidden fauna in the background that set the mood in the original Uprising level.
Overall, I think Halo 2 Anniversary's levels are far better than CEA's. They look better, they often (but not always) sound better, and they're far more faithful than most of CEA's to the original.