I know you weren't asking for other IDE recommendations, but I thought I'd give you perspective from someone who is almost exclusively a VS user and loves the IDE (well, up to VS2010, or VS2012 with 2010 colors and icons).
When it comes to the occasional PHP project, I just use an IDE geared toward PHP development. Admittedly, it has been a while, but when I tried using PHP extensions for VS in the past, debugging, unit tests, etc... all seemed to require a ton of effort or didn't quite work the way I wanted them to. I would have loved to use VS for all development, but in this case, I felt like the tool was too weighty and not quite compatible.
In my particular case, I use Netbeans because it is free, lightweight, and it just works. My projects are more portable to other non-VS developers and adding PHPDocs and PHPUnit support was really easy. I'm sure there are other good IDEs as well.
When it comes to the occasional PHP project, I just use an IDE geared toward PHP development. Admittedly, it has been a while, but when I tried using PHP extensions for VS in the past, debugging, unit tests, etc... all seemed to require a ton of effort or didn't quite work the way I wanted them to. I would have loved to use VS for all development, but in this case, I felt like the tool was too weighty and not quite compatible.
In my particular case, I use Netbeans because it is free, lightweight, and it just works. My projects are more portable to other non-VS developers and adding PHPDocs and PHPUnit support was really easy. I'm sure there are other good IDEs as well.