Heili vs Munin
Munin is a great tool built for monitoring. It can help to analyze resource trends and root cause. Even a default installation will help you get graphs with tons of data.
Heili vs Ansible
Ansible is agentless XXX XXX
Heili vs Ansible Tower
Ansible Tower is commercial product. It is a UI and dashboard add-on for Ansible Open source. Tower also comes with a REST API which aids automation tasks. You can also connect it to any LDAP including Active Directory system.