And folks using distros based on Debian Testing
Got kernel 4.15.0-3 in Sid. Seems to be running well got it about 24 hours ago on my most used install. Should be seeing it in testing in around 10 days (19th or 20th).
Distros based on testing but using their own repos or who configure apt to go for sid kernels may see it sooner. I know that Ubuntu used to get the new testing kernels installed pretty fast when they showed up in Debian Sid but this is 4th month of an even numbered year so 18.04 is due out on the 26th so I don't know if they installed that or not as I am not sure what their rules for new packages are now or if they granted an exception for this kernel or want to wait until the new release settles in for a bit.
Kernels that are in Sid are extensively tested in Debian Testing, by devs primarily, even before being released in Sid so kernels are generally pretty solid before Debian releases them.