The difference between ANBU/AonE and the other 'speedsubbing' groups is that AA has a very detailed subbing pipeline involving many people working on each episode. This also provides for the much higher quality.
There is not only a translator, but several translators, and an editor to check all of their mistakes. After the subtitles are timed, there are anwhere from one to three people who watch the episode, checking EACH and EVERY line for mistakes. Obviously, no one is perfect and occasionally mistakes still get through. The longer wait is due to all the steps that are carefully taken to ensure a good quality episode.
ANBU/AonE is not the only group subbing Naruto, or any other series, and in Naruto's case there are several groups of 'speedsubbers' that have the new episode out very rapidly.
If you are dying to see the new episode but also prefer the AA version, download a speedsubber first to satisfy your hunger, then download the AA version to keep for your collection and delete the other version. It's what I do every week.
If you're such an AA purist that you watch nothing else, then deal with the wait.
For those interested in joining the group, there is a test involved to test the required skills for each and every person applying. Go to the IRC chat rooms if you're interested.
Enough said.