I would have suggested this when I first started building PCs. In today's PC gaming environment where with a modern SB/Haswell Intel i5/i7 CPU the bottleneck becomes largely the GPU, a solid Core i5 OC will last 4-5 years. In that span of time, the R9 280/285 and 290 will become obsolete. That CPU will survive another 2-3 GPU upgrades. However, that FX8320 @ 4.2Ghz is already bottlenecking today and it will get worse with R9 300/GM200 series, even worse with 14nm cards and basically worthless with high-end 10nm cards.
The $100 you save today will cost you more over time since soon enough you have to buy a brand new CPU platform. To exacerbate the matters, AMD's platform has inferior I/O. AMD's SATA 3 performance is inferior, PCIe is outdated, and M.2 PCIe 3.0 x4 is basically MIA. To overclock that FX8320 to 4.4Ghz you will need another $30-40 for a good after-market cooler. Yet a stock i5 is faster in games and will use less power at idle and load. It's hard to make a case for the FX8000 series in this case unless you will absolutely not upgrade the GPU or consider a faster SSD/M.2 drive in the next 3-5 years. Normally I don't really care for power usage that much but in this case the difference will become rather large in overclocked states, but the FX8320 won't be close to an overclocked i5.