When you prestige on modern warfare 2 you lose all your weapons, perks, classes, challenges, and I think killstreak rewards(but I'm not sure). You keep your titles, eg.The Avenger etc. And you keep your emblems.
New perks and weapons
No, i think modern warfare 2 is better because there are new weapons and perks, and most importantly, silenced snipers.The answer to the question is more about opinion.Modern Warfare 2 does have better weapons and perks, but some of the perks in CoD4 are needed.
no you don't have to prestige in codmw2 if you want you can, just by simply pressing prestige in the barracks option in the xbox360 live menu. But if you do you will lose all of your weapons, killstreaks, and perks. however you will be able to go up more ranks, and kepp your titles and emblems.
you have to rank up to earn game modes, weapons, perks, and equipment
When you enter prestige mode, you reset your rank, you'll have to earn everything from weapons to perks to challenges. Titles and emblems are not reset though so you can keep them. You get a new challenge group called "Prestige" which can earn you some cool titles
All your guns, attachments, equipment, perks, level, classes, and challenges reset.
More guns. It continues the storyline from modern warfare 2. For multiplayer, there will be more perks and killstreaks and weapons. Also for multiplayer there will be more maps.
All of that depends on how you play there isn't a class that is the best for everyone.
Call of Duty: Modern Warfare 2 has new weapons, maps, perks and kill streaks. It will also have a Special Ops mode where you can play missions solo or with a friend.
No, the only thing you keep are your titles and emblems. You lose your guns, skins, perks, attachments and killstreaks.
No, there are no new weapons or perks in the Download pack, only 5 new maps, 2 of them are back from the old "Call of duty 4". its possible that they are only going to make map pack's, not new weapons or perks.
AK-47, ACR, MI6A4, Interventionz, Barret50., Scar-H, (Perks: Marathon,Cold-Blooded) many more :)