Air support you can call in (click 0 to bring up the radio menu, then hit 0 again then 1)
Land and air vehicles at your disposal
Patrolling enemies with armored cars and other firepower
Anywhere from 1 - 9 players with optional AI
In the current version the mission will end when you have cleared out all enemies from the base, but it will not say the objective has been completed. This is due to Arma 3 not having a working task system in the editor's script yet and me having to work around that.
The respawn system is a little stupid. It will respawn you exactly where you died after 15 seconds. Same thing as above, I had to find a work around and I am new to Arma.