While MS has to be commended for releasing version 1.0 the AJAX Extensions for ASP.NET on time and free of charge, the upgrade will not work for web sites which were upgraded from VS.NET 2003 and still have the tag in their web.config file. This will disable the AJAX functionality with no warning or error message whatsoever, prompting users to check and re-check the prescribed web.config updates and trying other fixes, wasting precious time. This issue has just appeared in the RTM version, still there is NOT A WORD about it in the migration guides, even though Scott Guthrie had blogged about this over a month ago. How many developer hours were wasted again by Microsoft sloppiness? How many will be pushed over the cliff into RoR land?