There are only 3 things that I consider so important to make the decision of change from SublimeText2 to PhpStorm:
Go To Anything
In Sublime we press MetaKey+P and we have a search bar that can find anything in our oppened projects.
Quick file preview
Either in the sidebar or in the Go to Anything window when we select any file, it opens in the editor instantanly for browse the file, and only creates a new tab when we start editing that file or double click on it to open.
Don't touch in my project files
It's redundant. I already feedbacked it in some other place. Its about the .idea folder it creates inside each project. It would be fine if it allow us to create that folder in some other place (like a workspace folder in our documents or dropbox).
I like JetBrain, and working with Magento and PhpStorm (with Magicento) is very very amazing. But I still feel that I'm faster with sublime, alternating between the projects quickly and easy, and mainly with the 2 first features above.