I just hit lvl 24 on my Engineer. The skill unlocked is Sonic Boom, which appears to be a point-blank AoE skill. Unequipped and at lvl 1, the description is

15 energy, 30 sec. cool-down, 6m range, 9-17 AE damage.

I am not too impressed out of the gate because of the 30 second cool-down, but I will probably have to play with it a bit to see. It won't replace Transferrence, but maybe it's worth it as a supplemental damage skill.

So what are the Commando and Operative Skills? Are they game-changers, meh or somewhere in-between?