VMware has a track record of pretty great reliability across a vast array of hardware. Yes, the APIs suck, but they're a case study on tech debt: vSphere is basically the Windows equivalent of datacenter APIs. They chose the best technology at the time (2009, which meant SOAP, Powershell, XML, etc) and had too much inertia to rework it.
Not to mention how flakey it is at scale. There is always some vmware guy who replies to me saying how good it is, but if you have thousands of VMs it is a random crapshoot. Something you just don't see with say AWS and Azure at similar scale. It reaks of old age and hack on hack over many years, and that is saying something when compared to AWS.
