The idea is very nice, I like to visualize the artists I listen to a lot (usually I am using last.fm listening reports). It would be super nice if you could improve on the final festival rendition poster. Maybe add some functionality (changing main/secondary color) and use more interesting typography.
It's a simple but fun tool and the process is super easy.
The festival poster itself should be improved. It's a bit disappointing because the web design leading to it looks more interesting.