This has generally been the case. The Fusion VMM is based on a relative/derivative of the Workstation 6 VMM. There's a lot of hidden options that are configurable via the VMX config, or if your VM is copied from Workstation, Server or ESX are honored to the best of OS X's or Fusion's ability. I'm sure undocumented implies an amount of unsupportedness too.
FWIW, I have run into the VNC Console Server, Serial port support, background snapshots, legacy VMs, legacy disk modes, and many other features.
See, the hard thing about being VMware is that our users are too smart.
Darn clever users! What are we going to do with them?
This is fabulous news, though. I was really nervous about moving VMs from my Linux workstation and trying them out. Now I'm not so concerned.
FWIW, I have run into the VNC Console Server, Serial
port support, background snapshots, legacy VMs,
legacy disk modes, and many other features.
Mmmm - think you could share those secrets
If you have a VM which uses these features, it should just work. As rcardona2k said, though, it's probably not supported.
>mmm - think you could share those secrets
Oh they're not secrets. Try searching the forums for VNC, e1000, serial ports, legacy, shared folders, etc. It's all here.
Also if you've used other VMware products such as Workstation, Server or ESX these are standard configurations copied from other VMs.