A whitepaper by Colin Eberhardt, Scott Logic Ltd. Recent advances in web technologies have resulted in a complex landscape for application developers to navigate. Coupled with the recent boom in new platforms, from desktops, netbooks, smartphones to tablets, making an informed and future proof technology choice is all the more difficult. In this paper we will set technology bias and politics aside to navigate the similarities and differences between Flex, Silverlight and HTML5 and give you the power to decide. This white-paper is aimed at technical decision makers who are looking to choose the correct technology for web application development.