AMD FX-8350:
+ Cheap
+ Acceptable performance in most cases, & performing no different than the 4670K in some games usually in 3rd person action/adventure or most FPS.
+ 6+ cores in the event that next gen games are far more optimized for more weaker cores over fewer faster ones.
+ capable of High OC
- Slower per core performance, performing as bad as an i3 in such situation.
- Some games prefer faster dual cores over weaker octo-cores, evident with Starcraft II.
- Requires a high OC (nearing 5ghz, i hear) to match an i5's performance. at stock. high OC = increased power consumption.
- Frame time not as good (though still within acceptable range) against an i5 in some games.
i5-4670K
+ faster per core performance
+ Better gaming performance in terms of frame rate and frame time, in most cases.
+ acceptable performance in games that demand more cores (i.e; Crysis 3).
+ integrated GPU in the event your discrete GPU craps out on you.
- expensive.
- Can't OC as high as AMD's, and runs hot when OCed.
- if it matters, outside of gaming, bad performance/price in multi-core applications.