What do you guys think of this build? Any issues?

Here is the build using PCPartPicker, easier to see.

PCPartPicker part list: http://pcpartpicker.com/p/d3KPRB
Price breakdown by merchant: http://pcpartpicker.com/p/d3KPRB/by_merchant/

CPU: Intel Core i7-6700K 4.0GHz Quad-Core Processor ($398.50 @ Amazon)
CPU Cooler: CRYORIG H7 49.0 CFM CPU Cooler ($43.53 @ Amazon)
Motherboard: Gigabyte GA-Z170MX-Gaming 5 Micro ATX LGA1151 Motherboard ($139.99 @ SuperBiiz)
Memory: GeIL Dragon RAM Combo 16GB (4 x 4GB) DDR4-3466 Memory ($139.99 @ Newegg)
Storage: Western Digital Caviar Blue 320GB 3.5" 7200RPM Internal Hard Drive ($0.00)
Video Card: Sapphire Radeon R9 390X 8GB Tri-X OC Video Card ($393.98 @ Newegg)
Case: VIVO CASE-V03 ATX Mid Tower Case ($44.99 @ Amazon)
Power Supply: EVGA 850W 80+ Gold Certified Fully-Modular ATX Power Supply ($117.99 @ NCIX US)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer ($16.88 @ OutletPC)
Wireless Network Adapter: TP-Link TL-WN722N 802.11b/g/n USB 2.0 Wi-Fi Adapter ($11.98 @ Newegg)
Mouse: UtechSmart US-D8200-GM Wired Laser Mouse ($0.00)
Total: $1307.83
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-01-25 11:49 EST-0500

You don't state what it will be used for so it is difficult to comment on the component choices. If it is a gaming build here is what I see.

- You need to add an SSD, a 320GB HDD does not make sense to me in a $1300 build.
- The Wifi card is only an N150, if you are gaming over Wifi you will slow down considerably. You have to check what your router is capable of and match that.
- You don't need an 850W PSU, you could save money and just get a 650W, this will still support a good overclock
- 16GB of RAM is a nice to have but not a need to have here. As well, it is not worth spending money to get anything over DDR4 3000. Only CAS16 as well.
- I am very unsure of the case but I suspect it is low quality. Can't find anything about it on the web which is not a good sign.

Here's my counterbuild

PCPartPicker part list: http://pcpartpicker.com/p/trym6h
Price breakdown by merchant: http://pcpartpicker.com/p/trym6h/by_merchant/

CPU: Intel Core i7-6700K 4.0GHz Quad-Core Processor ($398.50 @ Amazon)
CPU Cooler: CRYORIG H7 49.0 CFM CPU Cooler ($43.53 @ Amazon)
Motherboard: Gigabyte GA-Z170MX-Gaming 5 Micro ATX LGA1151 Motherboard ($139.99 @ SuperBiiz)
Memory: G.Skill Ripjaws V Series 16GB (2 x 8GB) DDR4-3000 Memory ($104.99 @ Newegg)
Storage: Samsung 850 EVO-Series 250GB 2.5" Solid State Drive ($84.34 @ Amazon)
Storage: Western Digital Caviar Blue 320GB 3.5" 7200RPM Internal Hard Drive ($0.00)
Video Card: Sapphire Radeon R9 390X 8GB Tri-X OC Video Card ($393.98 @ Newegg)
Case: NZXT Source 220 ATX Mid Tower Case ($44.99 @ Newegg)
Power Supply: EVGA SuperNOVA GS 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($69.99 @ Newegg)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer ($16.88 @ OutletPC)
Wireless Network Adapter: TP-Link TL-WN722N 802.11b/g/n USB 2.0 Wi-Fi Adapter ($11.98 @ Newegg)
Mouse: UtechSmart US-D8200-GM Wired Laser Mouse ($0.00)
Total: $1309.17
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-01-25 12:12 EST-0500