Note on the issue of ammo. It seemed like most of the podcasters have played alone through the campaign. When playing alone, your squad members have infinite ammo, meaning you don't have to share. If you have two friends running the campaign with you, those boxes now have to be split between three people, and that's where the low ammo problems start to show up. Also, Scientists are amazing. The entire time I was leveling my other three classes for Prime Mode, I really missed the mobility of flight.