UPDATE: This information is based on older AOS 4.6 version , for comparison between AOS 5.5 and Vsphere, plese read updated version.
For most implementations requiring basic hypervisor functionality Nutanix KVM-based Acropolis Hypervisor (AHV) is a good choice, even with some functional benefits over Vmware vSphere, cost wise AHV is hard to beat as it comes for free with Nutanix system. Please visit Josh Odgers’ blog for a good description of benefits using AHV.
However there is less information available on cases where Vmware hypervisor might be better fit or the only option. Like always there are fringe cases where a solution isn’t optimal or doesn’t fit at all, that is true also for AHV.