This question may asked so many times. I google about it and got lots of discuss generally. After reading all of them, I go to
a conclusion is choose the framework which your understand to it is the most. But we are willing to lean new language or framrwork to make our app better.
So we need some advices to determine which framework we should go with. So I'm posting here, hope
someone can give some advice from real experience when working with ROR and some PHP Framework.

We are developing a web application (it somehows like a file management sytem with multi users, drag and drop user interface,..). Our application is really a back-end for a system which runs on embedded device. We
are in progress to determine a "good" framework for our need.

Our purposes:
1. Build a business web application.
2. Easy to maintain, update.
3. Easy to scalable.
5. Easy to separate test& live environment.
6. Great performance. (We have like 1000 devices is getting data via our)
7. Easy to deployment.
8. It already has a many components/modules for general purpose such as: ACL, Authentication, Uploading, Picture processing,...
9. Have a great community behind the framework to support for it.
10. Unit testing.

One thing I notice, code in Ror is very short. To do the same purpose, we can just use some line of code in ROR compare
to PHP. This is better for us. Also we want to use AGILE method in our project. The reason is our product keeps
changing to meet to the need of customer. So I think AGILE method is better than for us than WATERFALL method.