Developing applications for touch devices is hard. Developing touch based applications for multi-user input is harder. The Multi-Touch for Java (MT4j) toolkit supports developing touch based applications for multiple users. In this paper, we outline our experience using MT4j for developing a number of software applications to support developers working in co-located teams. Our experience using the toolkit will help developers to understand the nuances of the toolkit and design issues that can be applied to other toolkits for developing multi-user touch based applications.