3A is good but window doesnt match seat location if you care about that. I like 1A but i dont carry on much so YMMV.
Travelling alone, I would stick to the A seats
I had 3A on the 3:00pm ORD-DCA flight. I would have probably chosen another seat if I knew about the window problem. Food service consisted of a choice of mixed nuts (standard AA nut mix except cold) or premium snack mix (the kind you get on short mainline flights in F). I was actually booked in F on DCA-ORD a few days ago but the flight got cancelled due to weather issues but the 738 that I was put on left within 45 minutes of the original flight and left on time. I don't know whether that was because the CRJs are less able to withstand the tough weather conditions or because of some other reason.