It literally takes you less than an hour to create a realistic usable CRUD app (that would take you at least a few days in the traditional way) without learning anything new. Generate a DSL (a Resource) and add one line per field.
Avo knows how to read and display in a rich way, handle creating/updating records using your already in place validations, add associations in a giffy and one-liner file uploads. If the provided fileds are not enough you can create your own. The Rails developer can forget about building a front-ned for their admin panel/back-office area.
When you need to break out from the CRUD, Avo makes it easy using regular Rails code and erb templates.
Maintenance you say? There's no real maintenance here. You don't generate any templates for your CRUD interface, but write declarative code with plenty of options to create the best experience for your users. Avo is beautifully packaged away and will not pollute your app with business files (only configuration files). Everything is abstracted away in the background so you get easy-updates by running one simple `gem update avo` command.
Large teams will move in a uniform way building the same UI all throughout the app.