We're using a Joomlart template for our client investeens.com. It is developed with Joomlart's new T3 framework, which is incredibly difficult for no apparent reason. As each template company diverges with their own framework, we as developers and implemeters have to struggle with understanding these frameworks in order to provide customization for our clients. Do we really need this endless acceleration of complexity? Do these template perform that much better?
Here is a link to Joomlart's T3 framework:
http://wiki.joomlart.com/wiki/JA_Template_Framework/FAQs
Good luck to you!