Thanks for the quick response, André.
Unfortunately, the acceleration kits move you to VMware vSphere with Operations Management.
Given the small size and static nature of my environment, I've no interest in Operations management or its extra cost.
Just based on the list pricing at the VMware online store, using the Acceleration Kit would cost about $7200 more than purchasing VMware vCenter Server Standard and 18 CPU licenses.
I know that I wouldn't have to pay that price, but it's indicative of the cost difference between those two options.
The Essential Plus kit allows you to use vMotion, but not Storage vMotion, so I can move my vm's between hosts at will, but cannot move them between datastores.