Call me old fashion, but whatever happened to grok, learn, read, write, and eventually knowing how to do what you want? I'm not trying to say that CSS frameworks have no potential or aren't interesting, in fact I'm not going to say anything at all; instead, I'm speculating that probably 2/3 of the people downloading and using them are doing it wrong since they see these _frameworks_ as an answer to not knowing how to do what they want.

This probably comes up a bit but what is the advantage of a CSS framework that provides a heavily pixel focused grid system for quick prototyping over say tables? I prefer CSS by far to tables (so much that I don't use tables for layout anymore) but it seems like these grids are just CSS tables, and with the overhead etc. if you are designing in a table mentality you may as well use tables.

CSS frameworks like this can be useful and harmful at the same time, depending on what your goals are. If you need to prototype something fast they can be invaluable. But they can also become a straight jacket and require littering your layout with what are in effect, as nopassrecover mentioned, almost table cells (especially with 960.gs). All these non-semantic divs with proprietary id's break down the concept of separating content from layout. So when you want to move away from the CSS framework in the future (to say, accommodate some specialized ad unit or something) you have to go through the pain of re-writing your layouts. You have to judge how extensible the layout needs to be in the future when deciding to use these or not.

I like using Blueprint CSS because it helps me design my sites in a true grid layout. Right now I am all about grids and really think they are a pleasing layout.

My experience with CSS is very high and I have cut my teeth writing barebones layouts innumerable times. So, I don't feel like I am cheating or using the framework to do something for me I don't know how to do on my own. It is a tool that accomplishes my goal a lot faster.

Plus, as content needs evolve on a site, I have the framework that makes it easier to add content divs that play nice with my existing markup. For example if I want to create a nice (1/3) (1/3) (1/3) set of columns below my main content div...the framework has solid classes to do that without me fighting browser issues.