I hope we see more B350/B450/X370/X470 builders in here. Not only are you getting good value, but hopefully you all may put more pressure on the mobo OEMs to keep up that UEFI support. Squeeky wheels and all that.
Make some noise if they are not taking care of your needs. You are just as important as the x570 buyers.
I have a Gigabyte B450 AORUS PRO WIFI board, with an R5 1600 in it. I just ordered a new 3rd-Gen R5 3600.
I'm curious, if I can get PCI-E 4.0 to work in this board.

I want to test out a PCI-E 4.0 x4 NVMe SSD. (When I can get the funds to buy it.) The newest BIOS update (besides the NPRP "press" BIOS beta), has AGESA 1.0.0.2 in it, and it says "3rd-Gen Ryzen CPUs
fully supported". Under the CPU support list, it does list all of the new 3rd-Gen Ryzen CPUs (including the 3950X!!!! 16C/32T!) as supported, as of BIOS F40. (Bolded emphasis mine.)
So, my question is, by saying not just "supported", but "FULLY supported"... do they mean that these existing B450 boards, support PCI-E 4.0 peripherals, like dGPUs and NVMe SSDs? I'm crossing my fingers. If not, I guess that I'll have to drop another $150-250 on an X570 board to get some PCI-E 4.0 x4 NVMe goodness. Oh well. Have to wait a few months in that case, then.