I'm finally settling on my crew skills and I've decided to just keep 1 Mission Skill. Between Treasure Hunting and Underworld Trading, which is more profitable?

Thats a tough one, I have both on alts. If I manage to get some mission discoveries for UT I bring in alot of credits from selling the grade 6 epic metals (about 5k per, maybe more), however I have made a fortune on selling companion gifts with TH because you get the fragments that you can turn in a vendor to get rank 5 green, blue, and epic quality gifts.

 

If you like a surpise (which I do, its seems more interesting) take TH... I find it exciting to see what I get in my lockboxes.

 

I have no experience with TH at a max level, since I stick to lower/mid missions to grind out fragments for gifts.. but I hear you can get epics, and orange pieces from lockboxes (I have had a few to confirm this)