You lose gun unlocks. So you need to level up again to be able to use most guns again.
Guns WILL keep all unlocked attachments and Camos.
You WILL keep your Emblems/Patterns and Callsigns.
You will obviously keep Permanant Unlocks (You can pick one once every prestige)
You will have to unlock what you want with unlock tokens again. You may have noticed you don't get enough to unlock every gun and scorestreak. That's intentional. So think carefully before you unlock something.
Master Prestige, is gained after 10th. This will unlock everything (Guns & Scorestreaks), so you need not to worry about unlock tokens.
You get a choice of one prestige award every time you do. You can Reset your stats (I don't recommend it really...), Reset your unlock token purchases (Refunds them back, allowing you to pick other things), and probably the best option, a new Create a Class slot. This replaces the next default class.
That should be everything...
So there's the perma-unlock, and a prestige award? Is that for each time I prestige or just this first time? And what's a recommended prestige award to pick out of those? I'm thinking a new create a class sounds good...
You get a perma unlock and prestige reward every time you prestige. CaC slots are usually the best bet for a prestige. Problem being you can only have 10 classes and there are 10 prestige levels so you can only take CaC 5 times. Also they do not carry over, so if you don't use it, you will lose it the next time you prestige.
replay and challenge. I stayed at 55 for a week before I got bored and went into prestige. You also get an achievement for what it's worth.
TC - Ghost is great, but I didn't pick it till my second prestige. I felt that a high level weapon would be more useful. I chose the scar and never really regretted it. Most of the weapons I use were lower level like the PDW - DSR - and S12. I did miss the LSAT and I am kinda glad that I didn't chose scavenger - to a point. EMP and ammo go quick with the S12 and an SMG, so if you use equipment a lot - think about scavenger.
If there are two evils, I'll try the one I haven't done yet. Gamer tag: Spinal101
Dunno if you've prestiged yet but you get a prestige award and you can pick another create a class slot. However if you pick it it overwrites the default class with ghost so unless you use your permanent unlock token on ghost you won't have it available til lvl 55.