The fact that it isn’t an apples to apples comparison doesn’t stop people (including myself) from throwing them into the ring for a deathmatch.
Although I spend a significant portion of my day talking to Rails developers, I still prefer PHP. In fact, There many opensource products avaiable in market. I understand the Rails philosophy of helping developers write good code by forcing them to use a structured framework, but the more advanced an application becomes the more difficult it becomes to work within that structured framework.
In addition, Rails performance is a major issue. Many people argue that development is faster with Rails, a factor which offsets the additional hardware costs, but this still has yet to be proven. I will definitely agree that prototyping is faster in Rails, but extending an existing Rails application (to replace the framework’s default feature set) becomes more cumbersome as the application grows larger.