In my opinion:
Servers -
Main still has intermittent problems every week or so it seems, and when they go down, the entire thing just goes.
PS recently had some problems too, but for the past two problems I noticed, only one channel went down and the other was still functioning.
Economy -
If you're a casual player, there's nothing too problematic in Main. If you're the kind who wants medium-high end equipment though, you either need to sell AP or play the market really really well, buy really low and sell really high or something. Or get lucky in drops (ha). Prices for those things are rising insanely due to shitty drop rates (low supply) and a lot of rich people who are willing and able to pay a lot (high demand), be it market players or gold buyers.
PS, inflation for medium-high is still pretty well controlled thanks to 2x drop rate increasing demand and no extra gold rate, but I'm pretty sure high end stuff are still very expensive.
Community - Main server's still nicely populated after the sorc bug was fixed, but a guild in PS is nigh compulsory if you want party shit done without waiting half a day. Less people also mean there are less guilds that are very casual since everyone wants an active guild to play with.
Item Mall -
Main's loyalty shop is getting better imo, it just introduced 5-slot bags that can be fused, though they're obviously bound beforehand. Ruby coins can also be bought with LP. Eidolon packs are still a complete joke, though
PS, personally it's not the perfect thing some people make it out to be, no offense. While custom costumes can be more easily gotten and certain LP things are cheaper, there are also some stuff that's AP only. And the 12 AP you get from playing 3 hours a day? You're not going to be able to buy anything worthwhile with it at all without saving for many many months. It's just a trick to get people to donate because you can't do anything with that little bit of AP, which is a waste, but if you top-up juuuust a bit more... Eidolon packs have been rebalanced to be less of a scam, yes, but the ones that matter (Endora, Serena, Verm, etc) are AP only, though this week there's a LP-pack offer that has a chance to give Serena or Cleopawtra. Ruby Coins are also AP only as of now.
Generic Eidolons -
Main, possible Key Frags from elites, fame quests, Temple each 6 hours, GH, etc, etc.
PS, fucking Eidolon Heaven. You get 2x more things for Elite and Fame rewards so that's double the chance, and you have a whopping 16x chance from Temple! 2 summoning stones * 2 eids per stone * 2x drop rate * 2x more temple runs in a day. The Eidolons that spawn in the Temple is still the same, though.
Dungeon/Item Mall Eidolons -
As I've said, getting them is still a complete scam in Main. Though, there are reported sightings of Serena and Endora in Lament of the Thunder Dragon dungeon, and the game is being transferred to a new publisher in Apr so I have some hopes that they'll stop fucking the players over.
In PS, you have a much better chance to get them, but you definitely need to fork over AP for them, unless you wait for LP promotions or something. Dunno how often they are yet.