Hardware is now not important
Unless you have a raging boner for a particular bezel or support contract, the compute hardware is largely invisible.
Nutanix knew this, hence why are openly becoming a software company (rather than reselling SuperMicro) . VMware are in the same boat with vSAN, with Readynodes largely outstripping the black-box variants out there.
Given that the rest of the options out there are also-rans (again, unless you have a raging Vendor allegiance or a Sales guy who regularly takes you on trips), it becomes two questions.
1. Do I buy Nutanix or vSAN?
2. Is HCI bloody right for me in the first place?