We have been fiddling with Unreal engine for a while now. Our first attempt was the tablet / mobile version of one of our previous projects;
Below shows the more recent desktop version of the scene with improved UI, details and effects. Anything is customizable and all interactions are performed in real-time, meaning you dont need to render loads of frames for each configuration. The quality is not photo-realistic, but it wont be long. Also the latest release of Unreal Engine features exports to html5, quality is lower than normal for now but this could also be a hugely successful marketing tool.
It appears we are entering a new era for visualization and property marketing which will transform the way people can interact with products and spaces.
Watch this space for a live project as we just picked up our first commercial venture using this software.