Appearance wise? Like, which had the best looking elites, best looking marines, master chief etc. Be it vehicles or Avery Johnson, pretty much anything.
I find that Halo 1 Anniversary had the best models for elites. Halo Wars had the best Mark V Spartan look. Halo Reach Brutes looked freaky to me!!!
It differs for all for me. H2A had the best Sangheili, Halo 4 has the best Chief, Halo 4 has the best Marines… I think 343i’s designs are the best so far. I don’t like their multiplayer armor or their Sangheili mandible designs so much, but they do a pretty great job with the other character models.
Halo 3 marines/ODSTs, Reach marines were more of today’s military look which was also cool. Halo 3 spartans, H2A elites/or Reach.