30 fps is fine as long as there are no framerate dips. I tend not to care that the game is only running at 30 fps. It gets the job done.
But when a game runs in 60 FPS, I'm like "oh man this looks all silky-smooth." And it's my clear preference over graphical effects/textures... usually... but not in the case of Halo.
COD games run at 60 FPS but they don't render environments that are as large as Halo's nor do they render destructible vehicles or objects that have their own believable physics. Everything in Halo's large environments explodes in the proper direction and almost anything can happen with the AI and gameplay. The 30 FPS is a very reasonable trade off as long as the game is stable considering how much is going on both on and off screen in the huge environments
Certain areas of Reach had serious slowdown which ruined the feel of combat (especially the first level). Can anyone confirm if Halo 4's framerate is more steady?
Halo works fine at 30fps, much like Gears of War but there is a big difference in 30fps and 60fps. I don't care if you love it or hate it, but no "military" FPS "plays" anywhere near as smooth as Call of Duty on consoles. Games like Battlefield 3 and Medal of Honor feel extremely sluggish in comparison. If Halo made the 60fps and went back to 30fps, people would notice. That's a big reason why you don't see any serious fighting games being released at 30fps, it affects the gameplay.