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 Pretty light-weight
Inferno weighs in at 9kb gzipped, which is light-weight.
Pro Fast performance
Inferno is one of the fastest UI libraries around and widely considered the fastest.
Use it however you want in a framework of your own custom design. When things change in the industry, swap things out instead of being locked in by someone else's design.
Pro React compatability
Using the Inferno compatibility package ("inferno-compat"), Inferno can support the vast majority of React codebases.
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 Some React components may not work with Inferno
Inferno and React have different public and private APIs. If 3rd party components use a private API then it's almost certainly going to break when you use it with Inferno.
Once React Fiber is implemented, even libraries that are currently working will break and will not be supported by Inferno.
Con Not very popular
Which can hinder one's opinion of its future, but the future of all "frameworks" is to break things into smaller pieces, so inferno very well might get used by the big names in the future.