I'm honestly not using any non-mainstream framework yet, but I'm at the window waiting for Aurelia. It seems really well engineered, and I need to learn a new framework anyway if I want to jump to Angular 2... They're hosting an AMA right now here on Hash node (hashnode.com/ama/with-aurelia-team-cijv67apt000o5…), they're very responsive and Rob Eisenberg seems to be a really nice person; it's good to have the chance to know "the man behind". Their business model is also intriguing. Anyway, after all these sweet words from me... I still want to wait for a release candidate (and hopefully a full fledged published book) before considering it for a project.