I've been doing a lot of development in PHP recently. I started programming in C/Codeworks, but it wasn't until I did some work in OpenCV and Visual Studio that I started seeing the value of IDEs. Having a good debugger is essential to resolving bugs in a timely manner. While it's possible to integrate a text editor, profiler and version control system with a debugger, it takes time to setup and maintain this tool chain, time that I'd rather pay someone else to spend.

You can do live debugging of Drupal using Komodo IDE and Xdebug, but you have to pay for the Komodo IDE as it's not currently possible to integrate with the free Komodo Edit. The docs are a bit out of date, but v4.4 applies to v6.1.

Komodo IDE is brilliant minus a few details. The integration with Xdebug is flawed which undermines my debugging confidence. Had ActiveState been a little more responsive in addressing these concerns, I would have bought it. I've now moved across to Zend Studio and Zend Server. The move was painful and time consuming but I've arrived at a better development setup as a result. So far, Zend Studio is a superior product, but only marginally and it doesn't justify its cost at over twice the price.

What I'm realising is that the deciding factor when I purchase a product is the companies responsiveness in addressing issues. I like the RedHat model, that you're essentially paying for support. Good support is worth paying for.