Ranked in these QuestionsQuestion Ranking
Pro Easy to use
Vaadin has a 'design mode' which allows developers to drag and drop components into a canvas and then provide the logic for every component. There are also a lot of third party tutorials and guides which help with the initial learning curve.
Pro Top notch documentation
The book of Vaadin is a must have for every developer that uses Vaadin to make web apps. It is an excellent reference manual and all around a great tool for every Vaadin related need. You can find and download the pdf online or get it for free in almost any Vaadin sponsored conference.
The online documentation is also very good. It has some tutorials and video guides.
There is also a vibrant community which sorround Vaadin, for any problem you may have there is a big chance that someone has already asked and answered that question on StackOverflow or in the Vaadin forums. If not, it will probably be answered quickly if you ask it.
Pro Modern, configurable theming
Vaadin comes with the Valo Theme, a Sass-based theme and engine that calculates styles based on configurable variables and making it easy to define a completely new theme with a few lines of SCSS.
Pro Easy to develop prototypes quickly
Vaadin has what is called the Vaadin Directory which is a repository of downloadable Vaadin components which can be easily used for development. To use something from the repository, you need to download the JAR file and add it to the project.
Pro Comprehensive documentation
The Sencha documentation is comprehensive, with detailed documentation and a number of examples displaying the various widgets, tools and themes.
Pro Supports MVC and MVVM development
Pro Supports Web and Mobile deployment out of the one framework or codebase
Pro Support for easy theming of applications
Pro Visual Design tool available
The Sencha Architect product allows you to visually build your application, or rapidly prototype a system.
Pro IDE Plugins available
A number of plugins are available for some of the commonly used IDEs (eg: JetBrains, Eclipse, Visual Studio), providing templates, refactoring support, hinting and code completion/generation, as well as management of includes and other time-saving features.
Pro Charting package included
Con Weak scalability
Since Vaadin stores the UI state and logic in the server, this means that for every user interaction a request needs to be sent to the server and the client needs to wait so it can know how to react. This leads to higher traffic and load times.
Con Sencha CMD is bloated and frustrating to work with
To do any meaningful development, you are stuck with CMD. There is a gulp task that will handle the JS concatenation, but there is nothing outside of CMD that can handle theming in their ecosystem.
In addition, CMD is based on Java, and is very heavy to run (600MB+ on Windows 10 to watch for changes in the application and recompile).
Con Sencha CMD (their CLI) is under documented, and out of date
Their latest release of CMD changed some configuration locations, but the documentation was not updated to reflect this. There is no reference guide on the json configuration files, other than the (unfortunate use of) comments in the generated json files.
Con They use proprietary extensions to SASS, making it incompatible with anything but their Fashion processor
On the plus side, you do not have to install ruby alongside CMD for more recent versions of ExtJS. However, their Fashion processor seems to only be available through CMD.
Con Too often breaking changes between versions. They have little concept of backwards compatibility
Compounded by the fact that there are now two "toolkits" in the same "version" of ExtJS, with certain components not existing in one vs the other.
Con The IDE tools are not sold separately - you must purchase the appropriate license pack
You get all the IDE plugins, even if you only need one. They should offer sell them individually, or continue to bundle them with a dev license pack.
Con Difficult to integrate with 3rd party software
Any third party library you wish to include has to be wrapped in some sort of component adapter. You have to do a lot of tweaking to get the build process right if you want the 3rd party lib to be bundled into your application in the right order.
Con Can be expensive
The framework is a commercial package, and the recent decision to start with a minimum of 5 users may rule out smaller developer teams or startups. Recently, they have started a program that allow essentially what are contractors to purchase single licenses, but not individual, independent developers.