If your focus is on V-Ray RT, and you want very fast rendering without a huge price tag, this single CPU tower is a perfect fit. It uses AMD's high core count Threadripper processors, which offer a lot of CPU cores for use with V-Ray Adv as well - but its specialty is support for up to four GPUs to boost V-Ray RT. With version 3.6 and higher, V-Ray RT can also utilize your CPU alongside the GPUs, so the many cores available on this platform won't be wasted.
Note that the trade-off with Threadripper is that each individual core is slower than the ones on our more compact, Intel-based single CPU workstation. While terrific for rendering, it means that this system will be a little slower for general modeling tasks in applications like SOLIDWORKS, 3ds Max, Maya, or Cinema 4D... but not much, and this larger tower supports twice as many GPUs.