In my opinion Slickedit works best in scenarios where you have a cross platform project that needs to be compiled say on both windows and linux and using the GCC tool chain for example
If it is windows only development (particularly if your application is using the various microsoft frameworks and APIs) Visual Studio is the way to go and is the best IDE for windows development.
That said, I am using slickedit extensively as I am working on a large c++ project which is cross platform. The editor provides all the features that I would require like cross referencing, integrated debug environment, integration with all the popular version control systems etc.
In the earlier editions there were some stability issues like frequent crashes and hangs etc. But the latest version is very stable and I have not faced many problems with it. Moreover the IDE can be customized and extended as per your requirements.