Ranked in these QuestionsQuestion Ranking
Pro Server side rendering
Deku can render it's components and data server side, then it sends those components as HTML to the browser.
This ensures faster initial loading time and SEO friendliness out of the box, since it's indexed as any other static website by search engines.
Pro Easy to learn
Since Deku is very lightweight and has a rather small API, there's not much to learn. It's pretty easy to get started and build something with it.
Pro Can use JSX
Developers using Deku can choose to also use JSX if they want to. This is especially helpful for people who are moving from React to Deku.
Pro Good performance
Deku's diffing algorithm is considerably faster and performs better than most libraries. The dbmonster performance mini-app written in Deku renders roughly 16% faster than other libraries.
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.
Con No support for legacy browsers
Deku does not support legacy browsers, or relatively old browsers for that matter. They only support the latest versions of the major web browsers.
Con Not a lot of learning resources
Since it's a rather new library and has a small community, there are not many examples where you can learn from out there. There are also few guides and the documentation is not amazing and has some parts that should be covered better.
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.