A system to please everybody.
A good administration tool needs to be a lot of things. It isn't just about basic crud anymore. You need it to be appealing to users so that it's a selling point for the project and users actually use it. It needs to help developers and not get in their way. The right features and no bloat. Ability to extend in a good structured way. It needs to give front end developers control over their code. The perfect CMS for all projects probably does not exist but by choosing the right tool for the job, a site can be a joy to build, edit and maintain.
What to look for
When evaluating a cms there are common things to look for. A well designed interface that is easy to use, the ability to manage all kinds of data types in structures that are flexible to match diverse projects, an actively developed and supported codebase, a community of invested developers and companies, the ability to manage rails model data, rails focused dev workflows, good user management and permissions, strong media management and all features developed to scale. It helps sell the solution if it has a good looking website with good documentation.
Strengths: Good support for managing rails content. Nice interface. custom post types. versioning. user management and permissions.
Weaknesses: No website. Barebones WYSIWYG. No modules. No hierarchical page structure. Media management doesn't scale.
Storytime is a very nice general purpose cms that really tackles the common needs of real world rails apps. Managing data, news or blog posts, pages, custom post types. Currently, it feels aimed at smaller sites and is the best cms for blogging in this list out of the box.
Comfy Mexican Sofa
Strengths: Powerful tags system to develop page content controls. Full featured with a propper WYSIWYG,
Weaknesses: No website, goofy name and quite basic interface make it a tough sell to clients and users. Templates kept in database, which is odd and doesn't allow for version control. User management not baked in. Media management doesn't scale.
Sofa is pretty awesome. It gets a lot right and has a lot of the features needed to adopt it as a regular CMS built in. It's weaknesses though are really holding back adoption.
Strengths: Scales well. Flexible. Good website. Some useful modules. Good community. Many developers are familiar. Nice interface.
Weaknesses: Common features like versioning, wysiwyg, advanced multi-selects, ordering, hierarchical, permissions etc need to be added with modules.
Probably the best admin interface for managing rails model data. Scales to huge data sets. Very flexible. A lot of functionality often needs to be added to it but there are some good modules for that.
Strengths: Great interface. Good marketing site and docs. Sites built in rails. supports real rails models.
Weaknesses: Asset management and site links, no live / draft system,
Fae is a good looking, nice to use CMS that would be a great choice for the right project. It only needs a few more features to be a great option.
Strengths: Nice website, good documentation and a nice admin interface. Great field options, especially matrix fields. Very easy to get started.
Weaknesses: Quite hard to manage rails model data within the interface. Missing a few key advanced features that could probably be added via modules such as user-forms and flexible-content
Pushtype is probably the easiest CMS in this list to get started with and would be a great choice for a content rich custom designed site.
Strengths: Visually beautiful. Nice professional website. Hosted version available. Good documentation. Visual approach to define
Weaknesses: Not very rails-y way of doing things. Doesn't work with real rails models.
Locomotive cms is real wildcard in the world of CMS. It has it's own way of doing things. It's aimed at sites that are all about content rather than functionality. It's built with Rails, but when using it, you aren't writing very much (any?) Rails code. For me, that's not a plus.
All of these new generation Rails CMS have a lot going for them. They have use cases that would make them a great choice, are well built and actively developed are only going to get better. Try one out today, and get building! Feel free to discuss your Rails based CMS preferences and experiences in the comments below.