Google just blogged about the Google Web Toolkit, a development framework that allows you to write an application in Java and convert it into a working AJAX app. I've always felt that using a toolkit or framework is good when they work -- why reinvent the wheel coding low-level stuff when you can use someone else's to implement your own high-level stuff faster and easier? Unless your product idea is to actually make something low level. As in if you're Google and making a toolkit, say for AJAX apps.