CSS frameworks have nice styles inbuilt and ask you to focuses on the grids but still there is a bit of dependency and lack of freedom it provide.. If I need to generate a webpage by looking on a PSD based mockup screen ..either i will use the classes provided by the framework but if that actual measurements does not exist I need to again specify my own rules that will add upto my CSS filesize and if performance is a constraint as always it is…you need not a big size file..though its in kb but every drop counts.
Any comments and suggestions to use the framework in a best possible way.
Css frameworks are not like the regular code frameworks/libraries that provide functions that allow you to do your work faster.. it is more like having a starter file, that saves you the time of writing css that you use in all your projects.
Saying that, I really do believe the best way to use a css framework is to look at what css you use more often and create a homegrown css framework. Personally i use the same reset and typography rules for the majority of my projects. I do have a collection of different grids, but really that differs based on the type of project. Not all designs will work with a grid.
Before when I tried to use a pre-built framework, I found myself wasting time removing styles or working around some of the styles from the framework. That is just from my experience with frameworks, I do know people that love working with Blueprint and swear by it.