If you're a fan of customizing your character avatar to your exact specifications so that its unique look stands out from the crowd, Atlantica Online is not for you. The character creation options limit you to a small number of faces which look pretty similar anyways. The standardized armor system doesn't help either and you will find a number of clones hanging around the leveling areas.
If you are an explorer who just has to find out what is up that trail and behind the babbling brook, I can tell you right now there's nothing there for you to find. Everything can be found on your handy map/mini-map. Even supposedly hidden treasure chests.
If you love your fluff and cool pets that follow you around; sadly, AO is virtually fluff-free. What little there is usually purchased from the Item Mall. Even the usual vanity stuff like mounts, outfits, and titles have stats elevating them to the status of useful items.
But for everyone else, Atlantica Online has something that is sure to appeal to them. For the socializers, there are comprehensive guild and mentor/apprenticeship systems. They can communicate to peers of their level in the peer channel globally and will always be rewarded handsomely for lending a helping hand.
The killers will have their hands full with a combat system that plays more like speed chess than the usual hotbar mashing. There's plenty of PVE mobs to grind and when you get tired of those, there is a full-featured PVP league system (Free League) and weekly tournaments. If you are in a guild which belongs to an alliance of Nations, you might even find yourself embroiled in open PK called Wars.
The achievers will think they've died and gone to heaven as there are plenty of bars to ding. Level cap is 120 and there are also the 8 other mercenaries in your formation to level from scratch. Roughly 90% of all items found in the game can be crafted and there's many different crafting skills that you can learn. The aforementioned Free League also sets another bar to conquer as you PVP your way from rank 18 all the way to the top number 1 spot.
So go get your Bartle quiz done and see if AO is right for you. You really can't go wrong with the price of admission.