simply put
CUDA cores are app dependant (modelling programs, real-time scientific simulations, etc). they handle the complex-math inputs very well, but output at very low FPSs.
other GPUs (amd/gtx) are designed to parse shader code more fluidly, at higher framerates.
so if you are a 3d modeller, and do not play games, then telsa is the expensive route to take.
if you are a pure gamer, and the heaviest number-crunching software you use is photoshop or maya, then get a gtx580