AMD recently came out with AGESA 1.0.0.4 bios update that is supposed to fix the slow boot times, just waiting for the board partners to release the update.I'm using the Aorus itx board, I've tried it on the 3900x and the 3700x.
It's fine. The idle voltages were too high on the oldest bios it came with but it's fine now after I updated to the latest bios.
My grief with it is that it seems to take pretty long to post and on rare occasions it will reset to default values when it isn't able to post. (I'm Doing no overclocking btw, just setting the 4000 mhz memory I have to it's profile and fixed at 3600 mhz).
It posts slow on both the Aorus boards I have tried btw.
I feel like I've read mixed stuff about all the x570 boards so far and none of them are perfect.... and I'm not sure who's to blame there (AMD or mobo manufacturers). I'm not afraid to recommend the Aorus ITX x570 board tbh, I don't think there are really "better" itx x570 out there.
These boards just aren't as smooth as the Intel 14nm+++++++ boards :[
I'll post pics tomorrow.