After returning to Star Legends from being gone for...what, a year now? I joined right after beta but quit awhile later...

Anyways, I found I had a level 18 commando with like 1500 kills and no deaths. I still like the commando, but it seems engineers are much more efficient. However, I haven't tried endgame yet. My questions is- Which class does best in pve at end game? So far my commando has performed excellently but my mana gets used up like that. Will the commando improve in mana as I level higher? Or should I swap classes?

Any tips would be appreciated! Thanks!
-MM