On my HP ProDesk G3 600 SFF PC, I am able to use some of the AMT functionality: power functions, agent presense, system defense, etc.
It seems like the SOL is partially working because when connecting using either MeshCommander or a powershell cmdlet, I see on the target machine an icon in the upper right corner of the screen. The terminal interface is simply blank with no interaction using the keyboard. I have changed the BIOS settings back and forth for ANSI terminal to VT100 and back to no effect. I have contacted HP support to see if some BIOS updates have changed or removed some of the AMT features, but have heard nothing back so far.