Wiktor Zychla has assembled a tiny AJAX framework contest between Visaul WebGui, ASP.NET AJAX and Ajaxium. Comparing a givven scenario he checked bandwidth consumption, requests per second, etc. The results as Wiktor wrote them are: "The VWG is an
undoubt winner. It did a great job of serving the highest number of requests per second, 422, and is also a clear winner regarding the amount of data sent to and from the server."