Ranked in these QuestionsQuestion Ranking
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 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.