I help small businesses with setting up their WordPress site and whenever I get the question which premium theme I recommend I always suggest that they should go and check out Themes by bavotasan.com (in particular business oriented themes like Farben and Tango). Your themes perform and look amazingly out-of-the box on both desktop and mobile devices, and the built-in theme options customizer tool makes any further customization an absolute breeze. Thank-you.
