I use RoR and am very happy with it. Instead of "reading and feeling", try coding your app and see how things go. Even if you switch, by coding, you'll have made a lot of progress.
That's general good advice, and usually I try to match a project with a technology I want to learn and go code. It's the best way. In this case I'm trying to figure out do I learn python and use a python framework, learn ruby and use RoR, decide to use a PHP framework, just code the entire thing in Perl, ...
some points about RoR, (I checked it a few months back so they might have changed!)
- It does not offer an out of box solution to allow authenticated users to create content forming pages as part of a Web site. It offers you a web app framework and you could build upon it your custom CMS from scratch (and it will take you longer to do so)
- but there is a nice binding to the database through the framework
- at the time stability was a bit of an issue!
with all that said there are great applications built upon it such as 37Signals Base Camp
I am not sure what kind of applications you are looking for, but in general there are thousands of successful and big sites out there... for instance look at the sugar network, its based on Drupal
also if you mean built on CMS out of the box, I don't either, and you will have to customize it in order to make something useful, but the point is that with RoR you have to pretty much build from scratch whereas with other CMS like Drupal you already have many functionalities included in the core and you don't have to really reinvent many things, you just customize or add the ones you want
