In ancient times, Aion, a god-like entity, created Atreia, a world of harmony and happiness between its two main species, humans and drakken. The latter became hungry of power and caused a catastrophe in the planet. This produced two new races: the Elyos, representing light, and the Asmodians, who represent darkness. These races battle to seize the power in Atreia.
Aion is a MMORPG in which you are part of a given guild and need to accomplish several quests. You can choose among the two main races, and then choose the guild of which you are a member. You can choose among different types of characters, and fully customize your own, including its hair and skin color, clothes, eyes, and so on.
As you can see, this game is not very different to other MMORPGs. Nevertheless, it is fun and interesting to play, so if you enjoy this type of games, you may want to try it.
Now, the main disadvantage I found is that, after downloading and installing the game, it needs to download additional update packages, which are huge and can take several hours to download. Nevertheless, you can skip this step and go straight to the game, but you will be able to use only those packages installed.
Another drawback is that the game takes a while to load. Of course, this and the downloading speed will depend on your Internet connection and on the capacity of your processor. If you have a good connection and a high-end computer, then you may wait less time before start playing.