I've had MMA setup for a few years now and it mostly works but it's been devices based and I've never had it working based on device/user. For example we have a lab of Macs and we only want MMA available for a particular faculty member and not an option for students. If I scope it to a user it never shows up. We have to scope it based on device but then it's open for all users of that device to have access to using MMA.
Maybe it's a setting I have but scoping to a user never works.
As for 3rd party, there're apps out there but many are pretty pricey. We need something that's not crazy pricey that can replace MMA and be controlled through JAMF or a cloud service or server.