That's a really nice build! I like the choice of the GTX 1070 instead of 1080, I feel that the 1080 is too overpriced considering the 1070 is almost of the same power. Though 4k gaming is a bonus, it costs quite a lot for a 4k monitor and 1080p feels just right, no need to go overboard with 4k (it takes more power as well).

Truly, this is a really nice setup... Definitely a good choice with the AMD Ryzen, a 3.6 GHz processor really improves the build.

This is a great post, Hope you have fun with the build! :)