vCenter Server Virtual Appliance (vCSA) is still very rare in a production environment. This might change with the current enhancements to the scalability made in vSphere 5.5. The maximum supported numbers of the embedded database have been lifted to 100 ESXi hosts and 3000 virtual machines. From now on, there are only a few imitations remaining. I do not think that many environments hit the scale limit, so the only remaining limitations are Windows-related limitations.
Here are the limitations from VMware vCenter Server Appliance 5.5
The embedded Database supports up to 100 hosts and 3000 virtual machines. This only applies to the internal Database. The external Database requires Oracle and supports up to 1000 hosts and 10000 virtual machines.
As linked mode is based on Microsoft Active Directory Application Mode (ADAM) to synchronize data across multiple vCenter Server systems it is not supported in vCenter Server Appliance.
vCenter Server Heartbeat
VMware vCenter Server Heartbeat is a Windows Application and can only protect a Microsoft SQL Server database.
Security Support Provider Interface (SSPI)
The Security Support Provider Interface (a part of SSO) is a Microsoft Windows API used to perform authentication against NTLM or Kerberos.
VMware Update Manager
The VMware Update Manager is only available for Windows. You can't install it inside the vCSA but you can install it on an external Windows System and use it with your vCSA.
The View Composer is only available for Windows. But it is no longer required to install it on the same system as the vCenter Server. A standalone View Composer installation works with the Linux-based vCenter Server Appliance.