The Gskill memory seems to be best for Ryzen, I would recommend getting the 3600mhz as AMD are working on a microcode update that will support at least 3400mhz RAM, and AMD have said that Ryzen will support at least 3600mhz ram. If you're able to get to 3600mhz that would be an effective 500mhz overclock on the CPU from 2666mhz ram as the interconnect is directly linked to the memory speed and will give you significant improvements unlike on Intel chipsets where the memory speed doesn't make much difference to performance.
This video shows the performance improvements you should get with faster RAM: https://www.youtube.com/watch?v=RZS2XHcQdqA
Ive gone with 2x8GB of GSkill ripjaw @3600 that is on the QVL list for memory. Although that same list says that ryzen only supports 3200. I suspect i wont even be able to post with that. If i have to run it at lower fora bit then so be it.
My boards memory list is here (mines the F4-3600C17D-16GVK)
https://www.msi.com/Motherboard/support/X370-GAMING-PRO-CARBON.html#support-mem
No bios update since the 8th march