I don't agree about JQuery. The learnability is good and it's really easy to get things done very fast. But when the code base grows it becomes really hard to maintain the code if you don't know JavaScript very well and know how to structure the code.
That's why many people have started to use CoffeeScript and/or Backbone.js to write more maintainable JavaScript. But the CoffeeScript/Backbone.js route is harder for beginners but in the long run it's a much better choice.