When comparing Blocks.js vs w2ui, the Slant community recommends Blocks.js for most people. In the question“What are the best JavaScript libraries for building a UI?” Blocks.js is ranked 10th while w2ui is ranked 11th. The most important reason people chose Blocks.js is:
Blocks.js is just 16.5KB minified and gzipped. So it's pretty small.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Small footprint
Blocks.js is just 16.5KB minified and gzipped. So it's pretty small.
Pro Modular structure
Apps developed with blocks.js are modular in structure and make use of reusable objects. This makes these applications very maintainable.
Pro Easy and clean API
Any component is well documented and have an easy API to access validation, dataloading and handling user events.
Pro Lots of components/widgets
Library contains UI components like Datagrids, Forms, Tabs, SideBars, Toolbars and more.
Pro Small library size
Only two files need to be included 1 .css and 1 .js, together they are only 365 kb.
regarding to amount of components it is very small.
Cons
Con Relatively new
Blocks.js is a relatively new library. It doesn't have much support and there re not many people who use it. So if you run into any problems it would be hard to get solutions.