Nifty-50 does low f/number, that's all. F/1.7 in your case I think, which is one and a half stops lower than f/2.8.
If you like the narrow depth of field you get at that aperture, that's what you'll get. It's quite a good focal length for portraits on a crop camera, but not much else TBH.
Basically, nifty-50 is cheap, different and fun. There's a long nifty-50 appreciation thread going on here right now somewhere.