Hey so I've been running esxi on two of these nodes for a couple weeks now. One is running opnsense+dc 2019+ a bunch of other VMs. The other is running vcenter server (which is a damn resource hog) and a couple other VMs. No clustering yet though, still haven't figured out exactly how I want to run these things and don't want to kill it as opnsense is acting as my main wan gateway (for now anyway). Sadly it doesnt seem to want to do any better than 500mbps throughput with NAT enabled and 6 cores exposed to the guest, I guess I have to do some more tweaking to see if I can get speeds up. Also I'm not sure it's entirely the firewalls fault here, I wouldn't be surprised if my ISP is screwing up on their end, but I'll figure that out whenever I test it again with my edgerouter hooked back up.
Definitely worth $300 bucks tho, especially since I already had the memory. Each has 2x32GB 2666 RDIMMS which will probably get swapped out if I can find any slower memory since the speeds on these sticks are being wasted.