I've had a couple of tunes that spent couple years at garageband.com. During that time I've seen the review process come to a complete halt for several months. Then they went through several reorganizations, which pretty much ruined consistency of review process. My songs rolled back every time. In the end they just backcatalogued them.
Before there was a concrete ultimate goal - a record deal. Obviously it was unrealistic to achieve it, but at least that gave this whole enterprise some kind of a purpose. I am not sure what is their mission statement now. Possibly you will be doing it just for the sake of getting reviews.
The reviews are a separate issue. All reviewers are unsigned musicians like you. Therefore your music will not get outside of this closed circle of people. So don't expect huge publicity. Majority of reviews will be useless because they will critisize your genre, not your music.
Before you could collect points for reviewing music, which you could use for "buying" CDs from CD Baby. That turned out to be a bad business model and they dropped it.
Long story short - garageband.com is a waste of time, if you ask me.
