I was one of those people who wasn't a fan of halo at all, after buying it this week i was quite suprised, after all the bad reviews about the campaign, it is quite small but non-repetitive and isn't actually that small, there may only be a few levels but they're actually quite long and can take hours to complete one of them. I for one enjoy completing tasks with friends and i found the halo 4-player campaign quite cool, You can earn achievements together and the legendary mode is relatively easy if your playing with others, worth alot of Gamerscore too ;)
So anyway, a break down..
1. Long campaign levels.
2. Non-Repetative gaming during campaign
3. Co-op campaign
4. Xbox Live Matchmaking Ranks (sergent, ect.) which is fun to achieve.
5. Unlock new armour
So afterall, this is an impressive game, a must buy!