[jrgnsd]

As some commentars said, choose the language/framework that suits the problem.

That said, I have experienced and heard that the time made up by using Rails/Ruby, is much less than the time it takes to customize a Rails app to get it to do what you want. Especially when there's a lot of customization. What I like about PHP and frameworks like CodeIgnitor, is that customization is dead easy. You only write code for what you want to achieve, you don't need to work around the framework's preset functionality.

Short answer, it depends. A lot of customization, use PHP, something that fits with Ruby/Rails, use that.