Obviously I'm pretty new (like really new), but definitely main engineer. I play in the gat/mortar preset pyramidion a lot, and with all my ramming (Fist of the Unicorns. Fear its name, and cookies to everyone who understands where FOTUS comes from) he keeps everything from falling into pieces. Literally. However, if I play with a sniper set up, buffing gungineer with Lesmok rounds. If he doesn't count, gunner. A sniping ship is nothing without a good gunner.
Also, hooray for first post. *waves flag around*