I used it as I I was having problems with CleanmymacX after upgrading to Catalina 10.15.5. I ran it and all seemed OK, but before I emptied my trash it I checked it and there was nearly 500GB in there! It had moved all my skiing videos and other important stuff that I didn't want deleting! Why would it do this? They are now stuck in my trash while I work out a way of restoring them without it taking forever. I can't restore using time machine because of my recent upgrade to 10.15.5 either. Not happy.
Maintenance 2.5.0, 20 Feb 19 and OnyX 3.5.8, 20 Feb 19, have been released. They are both made by Titanium Software. I opened both apps and looked at their startup screens. OnyX has 4 areas (multifunction utility) to choose from. Maintenance has 1. Both are the same. I can’t see having the Maintenance app as they are both FREE.
MacUpdate repeatedly seems to get the version references incorrect. From the Developer's website
There is a specific version of Maintenance for each major version of the operating system.
Use the specific version, and don't try to use a non-compatible version.
Maintenance 2.4.9 for macOS Mojave 10.14
Maintenance 2.4.2 for macOS High Sierra 10.13
Maintenance 2.3.0 for macOS Sierra 10.12