On one hand, the AMD FX-8350 is only $30-40 cheaper than i5-4670K. I don't know if this would sway me in favor of AMD, (1) considering i5 normally has faster per-core performance, (2) i5 runs cooler (edit: more power efficient), and (3) FX-8350 is not truly 8 core. It has 8 integer cores, but only 4 FPUs. On the other hand, the FX-8320 is right now $80 cheaper than i5-4670K, so I guess it does save you slightly more change.
However, i5-4670K still remains a fundamentally "cheap" CPU, being priced $230-240 in today's dollars. And, i5-4670K remains effectively as fast as the more expensive i7 CPUs for single threaded stuff, and it's not given that your applications will use enough threads to benefit from hyperthreading in the i7. Relatively speaking, CPUs are so cheap now that arguing about whether you save $30-40 bucks by going with Intel or AMD is almost inconsequential. I remember when Pentium II 400MHz, Intel's top CPU, at the time of release cost $800, and that's in 90s dollars. Back in those days, it might have been totally worth it to buy a CPU that cost 3x times less and then overclock it.