The Gantry framework is really great and I have been using it for over a decade. The themes, templates, and plugins are work together really well. In addition, their paid Premier Support is second to none. Being able to have all sites built on a single framework

I used RocketTheme, as Billy Joel would put it, for the longest time. I loved it. I'm relatively tech-savvy and a rather amateur programmer. Yet, with RocketTheme, I was able to create and maintain a good looking site but tailor it more than 100% out of the box solutions. Also, there are options to get support through the forums and the response is fast and very in-depth. The forum itself is really good with a lot of information available to solve all kinds of problems. The integration with their Gantry system is also great for tweaking and moving sites from one theme to another or "sub-themes" that change colors and highlights. Gantry is very powerful and I can see how for example a programmer could streamline making sites with RocketTheme and Gantry for a living. The documentation for each theme is also very good. You have a lot of information on how to make the most of the themes and how to replicate the demo sites. They also have great plugins.