We have good IDEs for Java, C# and many other strictly typed languages. For some reason (this reason probably being code analysis and debugging process), IDEs for weakly typed languages are not so popular.
I know many developers who mostly use Notepad like text editors (as Sublime or Notepad++) for their development. Honestly, I am one of them. I even remember one of my web dev teachers in university saying, that real web developer should be able to open notepad and create a website.
So when I first heard of IDE for PHP, I was quite skeptical. I think the first one I used was VisualStudio based VS.PHP in 2010. And while I was impressed with what it could do, the heavy weightiness of Visual Studio killed all desire to proceed with it. I preffer lightweight text editors. :)
Although I did come back to it, when I was working on a complex word generating package, that required lots of optimization and became so complex, I needed proper debugging capabilities to finish it.
So if you are looking for a PHP IDE to use, check it out :)