i resubbed for a month almost exactly a month ago (to try ps4 version), ended up playing very little just wasn't that interesting second time around. definitely play as a tank or maybe healer your first time, queues are all instant and tanking is easy. either tank class is fine, they buffed up warriors so they aren't pathetic pieces of shit anymore although paladins still seem to have slightly higher survivability. you can run with pug duty finder alllll the dungeons/guildhests, CT tower as many times as you want, turns 1-4, and most of the regular primals. You will need static groups for the newer content like turns 5-9, primal experts, levi expert, king moogle. The last dozen or so story quests are gated behind king moogle (never did him so dunno).
game is worth the $10-15 you can buy it for on sale and play for a free month, beyond that its just like every other mmo and a super grind that isn't really worth it. ps4 and pc versions are beautiful to look at, ps4 runs great especially with remote play on a vita. dont get ripped off and buy the ps4 version for $40, get the ps3 version and its a free upgrade to ps4. you do need to run it once on a ps3 and login under your PSN account, but can use a friends ps3 to do it too. I think the PC version is still the best though.