It's hard to say who would win now becuz I've played all 3 classes and each has their good and bad part

Coms obviously have tons of armor
Ops do great damage in a short time
Eng can heal (not so well at high levels though)

I'd say eng but every time I face a com I lose y though they r either A: 2-3 levels higher than me B: I faced 2 ops and have little health C: I can't get the custom armor when they have it