I couldn't resist and put together an R5 1600 with the ASRock B350 Fatal1ty ITX yesterday. It boot the first time, but wouldn't POST after I configured some things in the BIOS. I left it alone for an hour and while talking with my girlfriend, she said the word "RAM" and that made me remember the issues people were having with RAM overclocking. Thanks to that epiphany, I realized the issue was the XMP profile setting for 2933 MHz. I tried on the stock BIOS, 3.40, then 3.60 and still couldn't get it to run on 2933. I was about to flash to 4.40 when I saw the 3066 MHz option and decided "Ah, what the heck, let's try it before flashing again." Lo and behold, everything works!
I flashed the BIOS back to 3.40 and put the case back together. It's not the cleanest-looking build; the board layout made cable management messier than I expected. I'll consider sharing a picture if I can find one that's not too sloppy. The M.2 version of Crucial's MX500 can't come to retail soon enough...
Don't know when I'll be able to put it through its paces, but I'm definitely excited to see what Ryzen is capable of. I think it'll be fine with most modern games, so I'm more curious to see how it handles Dolphin, higan, virtual reality, and video rendering with DaVinci Resolve.