I have a D3100 and it is an excellent camera. The single thing that I would wish for in it is better high ISO performance. Having that higher ISO will let you get hand-held shots that would not otherwise be possible. So if the D3200 has better ISO performance, it is worth a reasonable price premium.
Check at places like Costco for best pricing. I got the D3100, 18-55 lens, a 55-200 lens, a nice bag, and a decent size SD card, for the price many places were getting for the body alone.
I am not upgrading at this point, since I've only had my D3100 about a year. I don't plan to upgrade until I feel that my skills have outgrown the camera, which is going to be quite a while, LOL. When I do upgrade, it will be to whatever is the next big step up.
Of course "800E" is calling my name, LOL... but not going to happen.
working on it in Middle TN Nikon D3100
35 mm 1.8 Nikkor 18-55 mm Nikkor VR 55-200 mm Nikkor VR 55-300 mm Nikkor VR 150-500 mm Sigma OS MeFoto Road Trip w/Q1 ballhead Feisol CT3471 & Markins M20 ballhead