For me, I reckon the SPARTAN-III Program is my favorite. Reason being is that it’s just so interesting with it being top secret and all. I mean, I know the S-III’s are weaker than the S-II’s but after playing as the walking tank MC for a long time, I just enjoy reading about the S-III’s in Ghosts of Onyx and I am reminded that people are still vincible despite having augmentations and having battle armor.
Johnson was an S-I , so Orion for me ! The original bad@$$es