Aion has certainly increased in the last month or two, particularly due to the hands-on time the public has had with recent beta events (you can see all of our coverage of the ongoing beta here). Whether the game has won you over or if you're just watching pessimistically from the sidelines, you're probably interested to know when it will officially launch in the western world. IGN is reporting that Aion will launch on the 22nd of September in North America, and the European launch won't be far behind on the 25th of September.
Other notable MMO launches in September include Champions Online, and Cities XL (for some European countries). Even with its recently pushed back release date, Champions will still be out well before Aion if its 1st of September goal is reached. Seeing as all three of these games aren't really very similar, their close proximity probably isn't too much of a big deal, but it does mean that some of the largest MMO launches of the year will be right next to each other.