I've used AMS8000
The Shure AMS8000 is a system that is outdated currently and is replaced with the Shure SCM810. As for the Shure AMS8000 - We have been using this system in our City Council Chambers with 18 AMS26 Microphones. The system works okay in for what we need, but we are looking to replace it due to its age. Basically the AMS8000 is an automatic microphone mixer that "opens a gate" if you will to either open the channel for audio, or close it. Our system uses 3 AMS8000s, a graphic eq (because the system does have some noise from time to time), a feedback eliminator, and an amp to power our PA speakers.
The overall function of the AMS8000 is to try to eliminate noise caused from open microphones, and works okay for this purpose, however i would only use it to mic a meeting, not like a live performance.