ExtJs - best among current Javascript RIA frameworks?

Ext JS is a cross-browser JavaScript library for building rich Internet applications. It is a JavaScript library for building interactive web applications using techniques such as Ajax DHTML and DOM scripting.

Currently version (3.0) added support for REST and hosted in Sencha web site. It has a history of licensing changes which became stricter with time.

Pros

• Excellent out-of-box Widgets
• Wow! That’s what would be your expression when you explore throughExtJs widgets. ExtJS is like a superset of the widgets like simple label, textbox buttons to complex grids, drag-drop panel s etc. It also provides demo for remoting to invoke remote server methods.

• Good API documentation
• It has quite good documentation with tutorials, samples and user community.
• Active and currently most adopted javascript RIA framework
• Good code quality/readability
• Inline Editing
• Ext JS makes it simple to edit tickets inline. Providing inline editing of tickets without it is out of the scope of what we can accomplish this term. Without it, we would probably end up using a modal dialog box to create and edit ticket details.

Cons

• The generated code
• Footprint - The library is 500 KB in size (using mod_gzip could be reduced to 150KB). Loading time would is high for home page on web.
• CSS – very easy to get lost. It is difficult to find correct class names
• HTML – full of divs and overly complex generated code. Difficult to debug even with FireBug.
• Dual Licensing and not free for closed source applications
• Modified GPL 3.0 licensed. Free for open source applications but paid for commercial closed source applications.
• Customization
• Using ExtJs leads us to believe that the GUI would kind of desktop and rich. Customization is not easily achievable.
• Verbosity
• Loading even simple things requires few lines of coding which is simpler in plain  html or jQuery.
• Debugging and Error reporting
• Debugging is not very easy. Only GWT has bit better debugging in hosted mode among javascript frameworks.
• No Bookmarking and indexing search engine
• It is not possible for the user to bookmark a certain page . Since the objects are rendered by DOM manipulation, page can not be indexed by search engines
• Learning time
• Need quite experienced developer.

References

• http://workaround.org/node/260
• http://fictionalrealm.com/2009/04/javascript-ui-framework-comparison-or-why-i-choose-extjs-jquery/
• http://themindstorms.wordpress.com/2008/03/18/challenge-which-javascript-library-is-the-best/