If you feel like rewriting in Rails, make sure you consider the deployment factor.
In my experience, the only way to have a Rails app that is responsive and reliable without spending most of your time on deployment as opposed to on development, is having someone like EngineYard host it. But that costs 100s of dollars per month, which might be ok in your case, I don't know.
Maybe you want to go with Symphony instead.
I'm not so much against big rewrites, you just have to figure it out yourself if you think it makes sense.
I've been playing around with Symfony lately and I am very impressed with it. At first, the endless amount of directories seems to not make sense, but once you start to use it you'll see they make perfect sense.
Very easy to deploy as well given that it's written in PHP.
Why don't you try Code Igniter out? I fell in love with PHP again cuz of it. Plus it's pretty lightweight and snappy compared to Symfony. Not to mention they are pretty much similar in structure.
In my experience, the only way to have a Rails app that is responsive and reliable without spending most of your time on deployment as opposed to on development, is having someone like EngineYard host it. But that costs 100s of dollars per month, which might be ok in your case, I don't know.
Maybe you want to go with Symphony instead.
I'm not so much against big rewrites, you just have to figure it out yourself if you think it makes sense.