Guess this could quickly turn into a "which camera to buy?" thread. There are a few things I like about the 3200, but being about as entry level as it gets, most any of the choices above would be a step up. Now becomes the time to decide what step up features should be my main goal and which body gives the best bang for my $1K.
There's a used 300s here locally that I can get for just under $700 (body and grip). With it's lower pixel resolution, how does it stack up to a used 7100 for close to the same money or even more?
If you don't buy it let me know where it is......
KEH EX+ without grip is current $732.
If it is a clean copy dealo for you. Compared to your entry level kit/ cam it will absolutely blow you away...
I have extensively handled D7100 and IMO the D300s is without compare for crop camera, I have relatives that shoot Canon as well and the Nikon D300s is far superior and I have owned or extensively handled all of Sony offerings, the D300s is the bees knees!!
Big ISO shooting doesn't interest me, I plan on owning only fast glass. I shot in gyms with F2's back in the day at ISO 400 and managed a few keepers so I probably have a diff perspective from many, ISO 1000 to me seems positively magical and is more than satisfactory with fast glass.
Handle both if you can before you buy....the difference in feel to me is significant.
The D7100 is a fine piece of kit but not in the same league. Either will be amazing vs. your current gear.
YMMV if course.
Good luck