I spent a little time over the holiday break experimenting with Ajax development specifically with the December Atlas preview. Overall I am very impressed with what you can do with zero client impact.
One problem I ran into fairly quickly was that I needed to debug to the client side JScript I wrote. All IE was giving me was the “error on page” icon on the bottom left and there was no obvious way to get details on what the error way.
It took a little while, but I eventually found the Tools\Internet Options\Advanced\Disable Script Debugging option which is apparently checked by default. I unchecked it and now the errors are visible when I click on the error icon in IE...
Hopefully this tip will save someone else sometime..
On to bigger and better things!