Sold off most of the parts of my skylake rig and that alone paid for this. Saw one of these Z440 bad boys on eBay with 64GB RAM, a Xeon six core and a Quadro K620 (which I promptly sold for $50) for $300, including shipping. Hell of a deal. Got rid of everything else from my last build except for the drives.
Intel Xeon E5-1650v3 3.5GHz 6 core processor
64GB DDR4 ECC RAM (4x16GB, 4 slots free)
Gigabyte WINDFORCE NVIDIA GeForce GTX1070 8GB PCIe video card
LG GH24NS95 24X DVD/RW drive
HP EX950 512GB NVMe SSD via M.2 to PCIe x4 adapter
Seagate ST2000DM001 2TB 7200RPM hard drive
Windows 10 Pro 1909
2xUSB 2.0 ports rear
4xUSB 3.0 ports front/rear
Audio in/out jacks front/rear
The GTX1070 was $200 total... and the M.2 to PCIe x4 adapter was $16. The drives were carryovers from previous builds... the 2TB and DVDRW drives were free and the SSD cost me $85 a few months ago. So, for ~$600 this is actually pretty amazing.
Another view... the 700W (proprietary) power supply has 2x6 pin GPU connectors so a 2x6 pin to single 8 pin adapter is required to get the GTX1070 to work.
SSD + adapter
Windows 10 desktop