Collaborative Software Engineering (CSE) is a rapidly growing field of research, with commercial tools starting to incorporate new collaborative features into their currently single-user products. We have undertaken an empirical evaluation to investigate the envisaged benefits of code-level collaboration for tools that we have developed. Results of our evaluation show that for two typical programming scenarios, collaborative tools achieve task completion rates that are at least twice as fast as their conventional counterparts. Additionally, for a number of subjective aspects, the participants were strongly in favour of using the new tools. From these results, we are encouraged to continue developing our collaborative tools, and to investigate other aspects of such tools within the context of CSE.