Don't know why AMD insists on calling them an 8 core CPU.In reality there are only 4 physical cores and 4 Logical cores.The 4790K Also has 4 + 4 4 Physical + 4 Logical Cores.
Most people that build AMD systems are on a pretty tight budget.$350 Intel CPU VS a $200 AMD CPU.The Best AMD Motherboard is currently $219 (Asus Crosshair V Formula-Z) VS $350 for the best Intel 1150 Z97 motherboard.
Personally I would go with something like the Intel i7 5930k 6 cores 12 threads and the newer socket 1151.The Intel Z170 chipped motherboard is a beast.And who can't forget 3000mhz DDR4 memory.Just wish I had the 1.5k $$$ to build the one I want.
I built my PC on a very tight budget.Bought everything 1 piece at a time and when they went on sale.As of now I have $768 into it over the last 3 years.With upgrades.