I'm a male from DC who's been using AM on and off over the last 2 years.
Cons first: in my opinion it can become a little expensive so if you can't spend much money you should at least consider to try other good affair sites like Saphrina. Just keep in mind that if you are outside a metropolitan area most of the times AM will be the better site to use because they have much more members than any other site in this category.
That being said...
I've been using AM on and off for two years and during this time I have had several "hookups". From my experience, if you create an interesting profile, write decent messages (no copy/paste, try to tailor it to the woman's profile) AM works, no matter what everyone else says. Consider the gender imbalance you will find on AM, but on any other affair site as well. That is part of the game.