Okay, so I've managed to make it out a few times. Would have been more but I'm always the nice guy that goes back and tries to revive people that are down, even though I've been left behind on many occasions

Here's the best tips I've learned:
1> Build up your sentry gun. They are your best friend in this game. If you upgrade them all the way you can put down two and they are great at distracting those pesky Rhinos. They also earn you money very quickly. The vulture is nice but doesn't last very long.
2>Use armor piercing ammo. A lot of people like the explosive ammo, but from what I've read and experienced armor piercing is the most effective. Especially with those damn Rhinos.
3>Split up your duties on the team. One person upgrades armor, one feral instincts, one team booster, etc. Your skill points will go much further if you do this.
4>Speaking of skill points. Always go for the challenges. If it's a gun one then get that gun and help. People want to save their money sometimes but the skill points are more important. You will get that money back easily.
5>Shoot the barrier hives! They will go down much faster. I've even seen people use the grenade turrets on them and they were down within a minute or two.
6>Okay, so you've destroyed the last hive and it's time to arm the nuke and haul butt for the chopper. Before arming the nuke, have everyone go back to where the first meteor will block you and set their sentries down. This method works really well.
That's all I can think of right now. If someone knows some more please post.