I've just received my 15" 2018 (silver) with i7 2.6GHz, 512GB SSD and 560X in the mail today in Maine, though I paid extra for next day delivery and it's an off-the-shelf config so that explains the quick delivery perhaps.
So far, it's honestly been a fantastic machine - I just hope it's better than my Precision 5520 that this is replacing, which suffered from really bad thermals plus a host of other problems. I love the little touches like True Tone and the improved keyboard (this is my first Mac ever, but I've used my friends' MBP keyboards before), and macOS is running really well. It's running a little hot during syncing on OneDrive, but I know that OneDrive is a bit crap on Windows, so this is probably the same with the Mac version. I'll probably fire up Steam or something reasonably 3D-intensive later and try some games to test the Radeon out and see if there are thermal issues with the laptop. For my first Mac, this has been excellent!