I'm actually writing a book on Ext JS 5 Application Architecture right now - but it's still a while off publication. In comparison to the projects mentioned in

I'm actually writing a book on Ext JS 5 Application Architecture right now - but it's still a while off publication. In comparison to the projects mentioned in this article you're kind of looking at the difference between and framework and a library really. Compare Ext JS with something like Backbone and in addition to the way in which Backbone/Underscore helps you implement an MVC structure you've now got a whole host of UI widgets, a class/dependency system, an optional build tool in Sencha Command. The things that you'd say were feature-matches from Backbone would be stuff like Controllers (and in v5 ViewControllers), but there's a lot of stuff (like refs) to help that work with the UI components. I'd say that where ever there's an equivalent feature in Ext JS it's going to be a lot more complicated! This is a burden and a curse. Like the config system that was brought in for v4. Initially seemed like overkill, can occasionally be a godsend but when you're working on complex class structures can be a massive PITA. On top of that you have the licensing costs and indeed the licensing itself which was something that put people off of Ext JS a few years ago when they changed it. Plus I suspect "enterprise" shops will be interested in Sencha Architect too, which bumps up the cost. Sencha Command does wind me up a little bit because it feels like an opaque mess built on top of ant. I just wish they could use something like gulp and have each part be a little clearer. In fact if they opened it up to the community on github that might be enough, they're not charging for it so I don't see the harm.