Nikon D7100 is a Toshiba Sensor and has the highest QE of any current DSLR (60% which is astounding). So there is a lot of potential there. Correction - Sorry that should read Nikon D7200 not 7100 which is somewhat noisy.
I have read reports of some banding in dim areas but I think it was not chronic more the odd time and can be avoided but something to check into.
Fuji XE1 is probably the current king of APSc cameras with its Xtrans colour filter array one of the advantages is lower chromatic noise. Mine does ISO6400 at about the same cleanliness as my D800E but less signal
(less area of chip for one thing).
There is a comparison tool at dpreview.com where you can compare various cameras noise at various ISO levels and both in RAW and jpeg (where they usually look better because of incamera noise reduction being applied).
http://www.dxomark.com/index.php/Cam...(brand3)/Nikon
Greg.