Just like most of the previous Modern Warfare 3 Elite Content drops, the July update adds a new Spec Ops mission. Vertigo takes place on the Oasis hotel, which if you've played through the campaign, you'll recognize it from the end of the game.
For this mission, you're tasked with shooting down helicopters, parachuting off of the tower, then running across a bridge. Sounds simple and straightforward, and it ultimately is, but your difficulty level can make it a little more complicated. And as with the other Elite Spec Ops, there are a few achievements tied to this one. I'll offer up some advice for you, so you too can take care of business.
Apex - You get this one for just beating the mission. Play it on Regular, and you should have no problem.
Flyswatter - Destroy all helicopters in the mission. Again, nothing super difficult, just run the mission on Regular and you'll do fine.
Pinnacle - Beat Vertigo on Veteran. If you've been playing all the other missions, or the campaign on Veteran, than you already know what to do. Stick to cover, use flashbangs on all the enemies, and play it really safe.
To Jugger or to Jugger-Naut - Kill all the juggernauts after they land on Veteran difficulty. To do this, you need to not shoot down a few of the helicopters so they can drop off their juggernauts. Juggernauts are tough enemies regardless of difficulty, so take some extra caution. There are plenty of different weapons on top of the tower for you to choose from; so use everything they give you. Try to clump them together, use a flashbang, and let loose with an old-fashioned RPG.
Vertigo is a pretty simple Spec Ops mission. The first half takes place on top of the tower - there's a bunch of different weapons if you don't like the G36 they give you.
If you're going for the Juggernaut achievement, I recommend saving your flashbangs and grenades for them, since there isn't an ammo crate on top. Once you've reached the halfway point, you'll have to grab a parachute and jump off the tower.
Once you land, you'll find an ammo crate, so restock up. This is where flashbangs and grenades are your friends. I also recommend using the PKP Pencheng LMG here. You and your teammate will face lots of guys, so try to keep your reloads to a minimum. Even if you aren't going for the helicopter achievement, I still say to shoot down the choppers - it'll make life easier. Essentially, it's a straight run to the green smoke and the completion of the mission.