Leveling Up/XP

David Vonderhaar posted a thread  on COD forums he informs us how XP works.
Black Ops 2 has 55 levels in it. The total amount of XP is very similar to the amount needed to prestige in World at War and Modern Warfare 1. I’d say it’s easier to level up, because you earn more XP than ever before with our Medals, Challenges we make available to you, as well as the leveling up guns themselves which grant bonus XP.
He also informs us about when create a class is unlocked and other information, it is unlocked at level 4, like all previous CODs.

At level 4, we give you about a dozen things you can equip “for free.” This means you don’t have to spend an unlock token on them. It’s effectively one item from each category.
1 Assault Rifle
1 SMG
1 LMG
1 Shotgun
1 Sniper Rifle
1 Perk from each of the 3 perk categories
1 lethal grenade
1 tactical grenade/equipment
“You get a perk at level 5. You get equipment at level 6. At level 7 we unlock Scorestreaks. You get 3 for free and 3 you can optionally spend unlock tokens on. At level 8 we give you a Perk. At level 9 we give you new Scorestreak.”
Then at level 10 there is a pattern:
Level 10 – Weapon + Something Else
Level 11 – Equipment (either lethal or tatical).
Level 12 – Scorestreak