ME is where the IPMI implementation lies. It can be used over the network to monitor sensors, to access the serial port and so on. It also has an HTTP server providing a web interface to the same functionality.
AMT on the other hand provides its network functionality by hijacking the host's IP, and siphoning off traffic destined for its ports (16992 and 16993). This is one of the things that makes it scary, and just one of the differences between it and IPMI.
Source: I have worked extensively with AMT and built a semi-open-source Python management library for it in a previous job.
https://www.thomas-krenn.com/en/wiki/Nuvoton_WPCM450R_IPMI_C...
Oracle uses these: