Since you started the thread with a surprise of getting only one hit on your first post, it seems that you are a sociable person. The AT has more people on it, and more frequent town stops.
For those reasons and because you this is your first long distance hike, I would suggest the AT.
From what I have read, the PCT runs the gamut of hiking terrain and conditions, from desert to snowy peaks, brutal heat to stretches of ice hiking and fording frigid fjords (ok, not fjords, but it sounded better than creeks :tongue). I personally would not make it my first backpacking expedition.
Wild Hare