Gunslinger and Pirate captain

Hello !
I'm pretty new to the game, and i wanted to know your opinion on some classes since i can't choose myself (urh i'm weak).
In your opinion is the dps between Gunslinger and Pirate captain (with the class gem on both of them) is the same or not at all, which one is the most apt at being choose for some ST etc.
Would you consider that it's just really up to preferences or one of them is really lacking.

Thanks for your help :D