TLDR: Don't bother, its a waste of your time and its not meant for casual gaming at all, whatsoever.
Long version below:
PvP balance is nonexistent, the 'SpritMaster' class is basically a WoW warlock class on steroids with 4 different fear abilities (at max level) that add up to at least a half-minute of leaving your opponent completely helpless with zero ability whatsoever to do anything about it. There's no 'trinket' to 'get out of jail free' here. If you talk to those who play SpiritMaster they just troll with comments saying 'L2P' or 'GTFO' or w/e. The only viable in-game method to counter this is to glide at the proper moment (very difficult to pull off, especially with 3 other fears ready to go), to stack metric tons of magic resist (unfeasible since it gimps you badly in everything else and makes you useless against melee classes), or to try to stun them before they can get the cast off (better hope that they don't have cast-speed gloves or equipment). Its a clusterfuck, they recently gimped rifting horribly to the point where hundreds of thousands of people quit retail and either went to private servers or uninstalled Aion altogether. Private servers are a mixed bag and full of the usual bugginess and broken AI/scripting.
The grind is still there, its just been mitigated with more repeatable quests and more locations to do questing. Ignore the person who said they had to grind 2 mobs in an area, they obviously failed to read the quest text or bother to notice the quests around them. There are quests of every level and area and it flows very smoothly. You'll just end up quest-grinding rather than mob-grinding.
Manastone socketing. Basically imagine WoW's gem socketing but with up to 6 sockets per piece of gear and with a higher % of failure with each additional gem after the first, that's Aion's sytem in a nutshell. Oh, and if you fail, then ALL of those manastones go poof, gone. A stupid carryover from typical Asian MMO development crap. I've known people that have quit the game over this, after wasting 100+ million Kinah (in-game currency) just trying to socket items only to have the last one fail and wipe out all the rest of them. You can do manastone socketing from as soon as you start playing. You can also replace existing manastones after paying a fee to remove the existing ones (though removed ones are destroyed, naturally). There's 'combined' 2-handed weapons like staves and greatswords and such that have up to 12+ manastone slots so it gets very frustrating losing everything so easily.
Suffice it to say that there is no challenge in the game with PvE (most bosses are just tank and spank or absurdly odd tactics requiring a very specific ability of one class that you better hope you brought along or else you fail the fight, period). Example of this is the 'Nimba' fight (I forget the full name) in Draupnir Cave where he'll start self-healing to be near-unstoppable unless you happen to have a cleric with a specific stigma stone equipped that can debuff him to reduce his healing by 50% and make him killable. While some very expertly-geared groups can just burn him down, its still incredibly difficult without that ability. You got to not only find a cleric but find one that has it equipped and willing to sacrifice another very useful ability in order to have this one obscure pvp-only ability to use ONE TIME against this ONE BOSS. Yes, Aion's PvE is shit.
Oh, and you gotta love the 'PvPvE' instances where you have two groups of opposite factions PvPing against each other with mobs spawning all around trying to kill everyone so it just ends up being a giant clusterfuck, again. End-game fortress raids are just all about zergs. Giant zerg swoops in, settles into position, and then spams skills till things die. Opposing faction comes in slightly later and takes potshots at anyone who has low hp (you can see the exact hp of your opponent) or who strays too far from the main group, or whoever has low health. Continue until either defenders make a charge to nuke the healers (and wipe the attacking group) or until the attackers succeed and chase the remaining defenders to their death.
So yeah...avoid Aion. I'd say if you want a good non-commiting MMO you can try Sword2 (also known as Sword of the New World or Granado Espada) which basically is a pseudo-RTS/RPG hybrid that lets you afk while your 3 characters automatically attack, chase enemies around, and heal. And yeah, controlling 3 characters at once really is pretty nice, lots of strategy and each class has its own quirks which balance out against most other classes. Some are weak against one or two other classes, strong against at least one other, and average to the rest.
Then there's Forsaken World, a WoW-alike that breaks the mold with fairly nice typically-Asian features like a robust pet training/combat system (which WoW recently decided to implement in their next expansion, lol), guild wars, PvP servers that let you kill anyone at any time for any reason or no reason (pure open PvP), anti-farming mechanics, and quite a bit more. I've had an on-again, off-again relationship with FW and its still much better than most Asian MMOs. Not the best, but its up there. The best parts of it when compared to every other F2P game is that the cash shop doesn't sell anything overpowering or for significant PvP advantage, you can use an in-game NPC to trade in-game currency for premium cash-shop currency (meaning you can earn premium currency in significant amounts through purely in-game activities), and you can trade cash shop items among players or sell them in the very full-featured Auction House.
Oddly, things we take for granted in WoW are pure luxuries in the F2P gaming circle, so the fact that FW has those features is a nice plus. Drawbacks I'd say is that there's a huge mana grind (better buy tons of potions), stupid 'stamina system' that limits how much you can gather/craft per day (deters farming but only pisses off the playerbase), and one annoying crash bug that happens if you perform a specific action (combining pets) that can only be bypassed by changing channels.
That's way too much to read, so just Google for a TLDR, lol.
