If you want to blow a massive development budget AEM is a great choice; otherwise I'd advise you to pick a different content system.
This decision alone probably sunk multiple millions of dollars.
The platform license alone for their operating scale was probably a half million or a million. What you get with that license is... the world's most complex and difficult content management system, that you now have to develop your whole platform around. Since it's so difficult to learn and work with you basically need a full time AEM specialist team, which again blows your budget up potentially in the range of millions of dollars, and then continues to burn strong every time you need any kind of update.