– Defining the user interface is based on Swing syntax and principles, that is very limited use of design patterns, and not in the elegant manner found in AppKit (responsability chain, dynamic bindings, KVC, KVO, delegates instead inheritance). There is no real/elegant architecture, nor innovative. The provided features are limited to widgets, whereas AppKit adresses most of applications needs, thanks to proven best practices.
– Such a solution to generate Cappuccino client side would be long and not fun, as it would require to define Java wrappers/generators for each control. Moreover as previously said the AppKit is more than just a widgets library. This redondancy would also be unuseful, as client side service proxy (using CP2JavaWS) seems comfortable for agile development.
– Some controls (notably Table view) are limited in Vaadin. Most importantly, performances look really behind : while live scrolling, it takes many seconds to update the rows. The developers choosed then to display a waiting message (range of rows being loaded – however not accurate).
Cappuccino and CP2JavaWS allow live scrolling among thousands of rows without any pause (on WebKit), or really slight ones using Firefox. The lite client side application code in Vaadin may require more messaging with the server (the client side is less autonomous – probably no caching in table view, etc.), that might lead to this performance concern.
– Vaadin does not provide abstraction for media layer, contrary to Cappuccino’s implementations of Quartz/CoreAnimation above its DocumentBridge.
– provided layouts arent’s as evolved as the constraint based one from Cappuccino (with automatic recursive calculation).
-the interface builder, whose design is derived from Atlas/IB, faces same limitations as other common editors (as they do not follow the principles that did make IB great)
– the default theme, despite being (too much) derived from Aristo, isn’t as polished. We just can compare Vaadin Tunes with ThatMusicApp. Recent buyout of Sofa (that created Aristo) by Facebook tends to confirm their advance. Even Google didn’t try to compete in this area, where they have always been known to be weak.