Some are supporters of the old dogs IW and prefer the Modern warfare series, others are revolutionaries and support Treyarch and want the economy system.
I personally think Treyarch have ruined 2 COD games, and IW have created the greatest game of all time (COD 4) but I understand opinions differ. This is why lately on nearly every blog their is one guy going "Black ops is shit! IW FTW!" and another replying "Your shit, MW2 was a fail!" and the parries continue until it's bedtime. And this is sadly going to continue. I pray IW and sledgehammer studios make a game like MW2, powerful weapons with decent accuracy and by the love of god no economy system! But others will want balanced weapons* and it is going to split the community in half, Treyarch fan boys and IW fan boys, and this will effect sales and eventually, in the worse case scenarios, Activision will cancel COD from falling sales due to Treyarch!
- The weapons are balanced in such a way that their is no change is weaponary. You don't work to unlock higher powered weapons, and before you give me shit Treyarch fan boys Treyarch have said they didn't want Noobs being savaged by higher levels with better weapons. So because of this communist way of thinking we now have no change in weapons and an overwhelming number of people complaining about Black ops, myself being one of them.