So, for early content (ARR up to like mid STB) I like to do solo play. My reasoning is that most things un-synced is easy to accomplish in minutes, and for me to wait in a queue for 20-30 min for a dungeon no one runs is a little much to me. Once STB starts to include some party mechanics into trials then I enjoy moving into MMO style gameplay.

Story/MSQ, I stricly do solo. The solo instances really put a damper on my party whenever we are trying to move through the MSQ together. That plus specific job quests or long make it to where we end up splitting up for half of our time playing, so we just like to do that sort of content on our own and meet up for some other stuff.

I really enjoy buying/crafting/trading so that is MMO style gameplay for me though you are a solo crafter just playing a mini game and then throwing stuff on market soooo you could argue either way I guess.

Eureka/Bozja depends on my mindset. If I want to run Delerium or BA, then ya MMO style for sure but if I am just leveling my elements/resistance then solo for sure to allow myself to mindlessly grind stuff out (granted, way slower so not recommended)

I love the venues they have out there and housing district and how the players interact, for sure MMO style.

I am a collector, so there is a ton of side content I do (achievements/GC seals/tribals/ect) that I stricly do as solo play but again, that is just I can just zone in and not worry about social interactions.

Raids/extremes/ultimates are MMO style, but sometimes strictly just people I know/game with regularly due to skill level of party finder (and because I don't want to hold people back).

There is a ton I am missing, but I hope the mindset I have for my style of gaming comes across. Really, for long grinds/old content I tend to be solo (or I guess, the things that CAN more easily be solo'd). Otherwise, it is party play