Are there any coders out there that have real experience/exposure to both PHP and ASP.net? I'm a C# developer, wondering if any PHP frameworks compare to the robustness of the Visual Studio Development environment.
You're kind of comparing apples to oranges. PHP Frameworks are not an IDE (Integrated Development Environment) as I believe you're looking for. That being said, some of the PHP IDEs are quite nice, I liked Zend Studio when I used it. Let me test stuff quickly and easily, code completion, database integration, source control. There's others out there I haven't tried, but from what I hear there are other good ones out there.
For reference, frameworks are what you build your application off of. They do a lot of the heavy lifting for you and allow you to focus on the logic of your application rather than implementation details of basics. CodeIgniter, CakePHP, Zend Framework, and Symfony are a couple examples of PHP web frameworks.