The most well rounded out of the Bungie trilogy specifically with the campaign. Gameplay's incredibly polished, the level design doesn't suffer the pitfalls of either bad reuse like CE did or the lack of polish of 2's second half, and also shows Bungie's storytelling and direction at its most refined. The story does suffer a bit from being essentially what should have been Halo 2's last act, but I'd still probably say this is my favorite of the three campaigns to play regardless.