When comparing Can I use... vs Hackr.io, the Slant community recommends Hackr.io for most people. In the question“What are the best resources to learn CSS?” Hackr.io is ranked 6th while Can I use... is ranked 12th. The most important reason people chose Hackr.io is:
Instead of getting a recommendation from a single dev, you get recommendation from the entire programming community.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Supplies usage data for all countries
Pro Provides good list of resources
When serching for a feature you typically find a nice list of really valuable resources, such as spec on w3c website, and blog posts desribing usage in details.
Pro Community trust
Instead of getting a recommendation from a single dev, you get recommendation from the entire programming community.
Pro Recommendation for every programming language/framework/library
You can find Python as well as Jenkins.
Pro Nice filters
Free, Video, Book, Beginner, Advanced, etc.
Cons
Con Not that good for learning
It's a super cool catalogue for people who know what they are doing, just to check if their tricks apply to certain use case or project. It doesn't serve as a good starting point nor roadmap for css newbies.