My choice would be the Ryzen system because the 9900k, while an excellent cpu is basically going to be a "what you see is what you get" sorta deal. That platform/socket is the last of it's generation. There is no upgrade path or anything. According to the rumour and etc, Intel's 10th gen is going to be a brand new platform which won't be compatible with the intel 9000 series platform.
Compared to AMD, not only can you upgrade all the way to a 16 core with the Ryzen 3000 series (Double the cores of the 3700x) but it's supposed to be supported until the end of 2020 which means you can always upgrade to Ryzen 4000 series once Asus releases a stable BIOS.
So just for that, I'd pick Ryzen. If intel's current platform worked with their next gen cpus, it might have been a different story because then, I'd consider what you use your system for.
I see, and that makes perfect sense to be honest with you. Thank you! I do audio production, gaming, video editing etc... is my all in all system but just wanted to make sure i have a bit of room to upgrade maybe one piece of hardware like the CPU if anything before needing to upgrade the entire thing. So far Intel works perfect atm easy system no issues at all but I wonder if later on I may need more cores for other project etc...
Is it worth going X570 or X470 ASUS is more than enough for 16 cores later on?
X470 should be more than enough. My X370 is able to run the 3900X just fine and I am sure it can even run the 16 core 3950X as long as I don't overclock. The key thing is to wait for a stable BIOS since Asus's BIOS has been all over the place. The only reason to get X570 is if you want PCI-e 4.0 and Thunderbolt 3 but those are some expensive motherboards that won't make much of a difference for a very long time.