Mann vs Machine Co-Op Strategy

[Mr. Analog]

So, last night suffered a string of defeats, the main problem was people ragequitting (and one guy dicking around with the sticky jumper and not doing anything).

Turns out if you only have 3 or 4 guys it gets real tough real fast

Anyway, with that in mind some strategic thoughts:

Engineers!
If you are down a man or two stock up on Engies, though don't clump together and make sure you equip The Wrangler (your turret gets a shield AND you can send fire a lot further down the lane)

Scouts!
They get health from money, they instant respawn and vs robots they are pretty deadly. If you are a scout and you're in an area where a turret can distract the robot masses you're in for some fun times

Pyros!
You can juggle enemies with the airblast as they come over the top of the fence, you can also air blast enemies into mineshafts or away from the bomb drop

Spy!
Upgraded sapper can disable robots in a radius. Robots are exceedingly dumb and will not really notice your disguise (unless you are on fire)

All the other classes are important damage dealers but with the right combination of turrets and special hassle classes you can really do a number on the bots!

Info on the features for various classes in Mann vs Machine mode:
http://wiki.teamfortress.com/wiki/Mann_vs._Machine_(game_mode)