CPU counters at the VM level
The following screenshot shows the VM CPU counters in vCenter 5.5 taken from the C# client. The Collection Level column does not apply to vRealize Operations. Changing the collection level does not impact what counters get collected by vRealize Operations. It collects all counters from vCenter using its own filter, which you can customize.
In vCenter, there are 16 counters available at the VM level, and 11 of them are available at a virtual core level too. That means a VM with 2 vCPUs (or 2 virtual cores) will have 38 counters. A vSphere environment with 1,000 VMs with 2 vCPUs as the average VM size will have more than 30,000 counters! In vCenter, you can look at an individual VM to see these counters. Because VMs can impact one another's performance, you need a management tool that can cut across all of these 38 counters across VMs in all vCenter Servers. I find vRealize Operations useful because it allows me to slice and dice all of these counters across VMs...