We’ve been creating website exclusively using iThemes Builder Framework since it was version 2.1 and have watched it grow and get better over the years and is now at version 5 with full responsive design.
Back when starting web development and building WordPress real estate websites with limited knowledge of CSS and PHP we were really looking for a framework that allowed for content targeting but didn’t require us to write a lot of custom code.
Content targeting is where you can customise and target every single part of the page from sidebars, widgets and footer areas to support the content on each page. This is very difficult for many themes as they may provide a handful of individual layouts. Not good when you need to specifically target widget areas sometimes down to a page. You can use widget logic, but when there are a lot of layouts its next to impossible to use a widget plugin.
You can build any site with iThemes Builder. Most of my themes start from their Builder Air Theme which allows complete and total control over CSS as it is very minimal.
It’s funny, one of the main reasons for selecting that framework many years ago was their Styles Manager CSS plugin.