BLM will probably always be my most favorite to play, especially for 'lowman' content like missions/etc., namely because of how much it ends up being somewhat of a 'math equation' kinda thing. Adding more INT/MAB/etc. shows direct results, and a lot of your effectiveness comes down to skill and timing as opposed to a melee job where it's often just 'stuff gear onto various slots and tell yourself that it's probably better, even if your Tachi: Gekko is still somewhere between 400 and 4 million damage each time'.
RDM is probably one of the most versatile jobs I've ever played, and I probably play it more than anything else. RDM + THF combo is insanely good.. like, you can do just about anything in the game dualboxing that setup, given enough time. It's crazy how high you can stack Evasion and take on all kinds of insane mobs that are way higher level than you.
SAM is my favorite DPS class to play on Nasomi, very strong and versatile. DRG still holds a special place in my heart (it was my first 75 job), but I know that my SAM is just way more useful in most situations.
Honorable mentions for SMN and RNG. Both are kinda 'niche', but both make me feel good to play
