A few years ago, and to replace the massively expensive and complex-beyond-belief SAP system, I was tasked to find, recommend and then procure and install, a maintenance software system - admittedly for a small operation - but it still had to fill lots of maintenance objectives with relative ease.
I searched and found some 60+ systems available and reviewed them ALL one by one.
Some were too simple and designed for private pilots who didn't know what they were doing. Some were good but too complicated and some were far, far too expensive for what was needed in that operation (Some helicopters). I even found out some end-users and visited them without the "System OEMs" knowledge and got real end-user criticisms - quite valuable!
I eventually pulled three (all about £100K or less) for procurement review and all three demo'd their wares on-site before the middle one was selected, purchased and installed.
In all that work I found two rules applied...
1. There is no such thing as an easy Maintenance system - because aircraft maintenance isn't easy...in fact it is VERY complicated indeed! But some systems are better (More user-friendly) than others at doing the same job.
2. All systems can't replace paper. Instead, they follow a logical pattern of documented completions before a flight is released - if you don't follow the computer's logic, the system won't work! So, if your installing a system, the workforce MUST change their processes to fit the computer logic.
At that time, I bought a system for £25K + £Kpa for support and upgrades - and saved £1million pa overnight.
I can't comment on AMOS as it is now, but I only kicked it out due to its massive costs.