Practical .NET

I was one of the ones who jumped on the AJAX bandwagon pretty quickly.  I've built several private apps using AJAX, and really like it.  I like the fact that the web becomes more "rich," and more closely resembles forms in functionality.  The gains are enormous.

That having been said, I found myself asking the question:  Is it worth it?  I've found (so far) that doing things with AJAX takes at least three times longer, there's much more room for error, and cross-browser issues are brought to the forefront.  I have played around with the AJAX.NET framework a little, and have had mixed results.  What I got working was pretty cool, but do I really need rounded corners on divs?  It seems to me that a lot of their controls are gimmick-ey, and don't really have all that much to do with AJAX. 

I think my biggest disappointment with the MS AJAX.NET framework is it's complete failure when adding the framework to an existing project.  I could not for the life of me get it to work.  I spent three days fiddling with it, and nothing seemed to want to work.  I really have little desire to re-write the projects that I do have for the benefit of AJAX. 

So, is it all worth it?  Are post-backs really that evil?  I'm starting to think "No."  AJAX is cool.  I probably won't use it if I'm in a hurry.  It has its place, but is it ready to take over the web?  Should it?

Those are my questions...