This fall semester I have been working with a professor to take a directed study to assist the current Software Design and Development course. Unlike last spring's course, this semester the MEAN stack (MongoDB, Express, Angular, Node) is being used. One of the main reasons for using Backbone last spring was it's more clear separation of the MVC (model, view, and controller), however Angular had only gotten more popular and several people in the Computer Science discipline/major at UMM had used it. Having already committed to do a directed study for the course, I was thrilled to learn that we would be using Angular. This allowed me to have a fresh start for the main framework, while already knowing a lot about Node.js, Express, and MongoDB. I've been using Angular and now Yeoman generators (these are awesome) and I can say that I think it is an excellent framework and is incredibly powerful. I hope to continue using these frameworks for years to come.
I think that in order to learn to develop for a new platform, you have many hurdles to overcome, but that experience will add to your general knowledge of computer science, and will make every new endeavour a little more manageable.