This is a really great build. It can run pretty much any game on max settings at 60+ FPS. It's also very cheap for the amount of power in the build.
The CPU is great for an average budget and the RAM is perfect for running the CPU to its max. The GPU, the R9 390 Sapphire... This beast of a GPU will destroy everything in its competition. With 8GB of GDDR5 VRAM you will plow throw the 970. Benchmarks are a amazing for this part and its just all around a great card. The RAM. For such a low price, 4 4GB sticks is just outstanding. The MOB. The motherboard doesn't really affect performance. It only affects the way the cards, CPU, and RAM works. The PSU. I have this build for myself and a 600W PSU is perfect for running all of the parts with extra space. The Case. The S340 alone is just an amazing mid-tower case. Add a matte black coloring and some crazy LED's on the Razer Logo just makes this shine in the night. The OS. Windows 10, although not stable, is still perfect for new games. New games are evolving and need new OS, Window's 10 is a prime runner for this staple. The Peripherals. First of all. These are personal preference. I think the K70 RGB is gorgeous and wonderful. The mouse G700s has enough buttons for a MOBA, FPS and RPG. The monitor is a great budget monitor and will stand for a long time.
Over all I think this build will last for a long time and is very worth while.