If you’re evaluating open source web frameworks and CMS’s for your projects, then consider the time vs customization tradeoffs. I don’t have a ton of experience evaluating the different technology options, but I have noticed a general trend.
On one end, you’ve got high-level CMS-like frameworks like Wordpress, Drupal, or Twitter Bootstrap. These tend to give you a working website out of the box, and the name of the game is customization. For commons chunks of functionality (like modal popups or accordion menus, you can typically find contributed open source solutions that just plug in and work. However, trying to adapt those plugin solutions in a customized way can leave you fighting against the machine which can be a real time suck. So for high level frameworks, features are cheap but details are expensive.
On the other end you’ve got lower-lever frameworks like Ruby on Rails, Symfony, or HTML5 boilerplate. These tend to give you less out of the box, which means you have to build more from scratch. Naturally, this makes tailored solutions and customizations easier. So for low-level frameworks, both the features and details take work, but you won’t face the cost of fighting the architecture in place.
Different customers need different things. Some people would love to use a theme that’s already out there if it will save them a couple grand of custom work. For others, that’s not an option. I think the best advice is to fit the tool to the job, not the other way around.