Ruby on Rails is considered very controversial among developers. We would like to explain why: The Rails doctrine gives us strict guidelines as to how problems should be solved. Most things have been well thought out and have an answer already. This reduces the control the developer has over the framework, but has the advantage that we don't need to think about the trivial parts. Ruby on Rails directs our attention to the essentials and makes our developers damn fast.
This is exactly why some startups like Twitter, Xing or Groupon have gotten big with this technology.