Abilities gained:
1) Supplies Max increase
2) Battle hardened
3) Combat Intuition
4) Sense of Perspective
5) Supplies boost (medic) believed ability
6) Kelvar plate (engineer)
7) Firewall (operative)
8) Adrenaline (medic)
9) Armor piercing ammo (Soldier)
10) Upgrade command post (Engineer)
11) Scavenger (Soldier)
12) Incendiary ammo (Soldier)
13) ???
14) Silent Running
15) Improved life boost (Medic)
16) Improved damage boost (Engineer)
17) Self resurrection (Medic)
18) ???
19) ???
20) Lazarus Grenade (medic)
5 universal abilities, 5 medic abilities, 3 engineer, 3 Soldier and 1 operative with 3 extra abilities
We are still missing a couple of abilities so its subject to change.
As far as playing classes its medic>soldier>engineer>operative.
Playing as a light you can continually keep your teammates buffed and resupplied. Also the firewall/boost command post to ensure the most gain for the entire team.
So what do you think?