+1 for the speed. Not many IDEs seem to care for that any more. Especially most java based IDEs. They feel so sluggish even for the most rudimentary of tasks (opening menus, launching, closing, autocomplete etc)
I switched from zend studio to phpstorm almost entirely due to speed, with product quality being the other part of what drove me. Fundamentally, an ide is still a code editor, and it has to do that at least as well as notepad++ or i will not use it.