This week I've had the displeasure of simultaneously reinstalling or updating development tools for both the Series 60 platform and the iPhone (Cocoa Touch). I've installed both toolchains before, but never this close together. It made me realize what a huge difference there is in the ease of use of these two toolchains.
Just to give you an idea, here are the separate bits of software I had to install in order to get S60 development going on my MacBook Pro:
For Cocoa development the only software I needed to install was, you guessed it, XCode. One install does it all. The extensions documentation was automatically loaded into the XCode documentation browser as soon as I opened it.
I think the lesson here is very clear: using third-party packages in your SDK is a big liability. It makes a developer's life much simpler if you can tightly integrate these components into the main IDE.