Like you, I'm more a back-end developer and attempted to pick Backbone initially for my SaaS, but I wasn't very successful with it.

Later I discovered Knockout and in 2 hours, I was up and running, and it never got in the way so far.

I can only encourage people to at least try the tutorials, it will be time well spent:

http://learn.knockoutjs.com/

  > It seems like there's too much complexity

Backbone helps you to do the things you understand. Knockout let's you do things you don't necessarily understand. Sometimes black-box approach is OK. Sometimes not.

Knockout, while it seems magical at first, is actually not so hard to reason about.

It's not really a "blackbox". It's quite easy to understand and extend too.

For instance, you can create your own custom bindings: http://knockoutjs.com/documentation/custom-bindings.html

This is about the only place where it gets low and dirty and involves you writing DOM manipulation code.

I'm not familiar with Knockout, but it sounds like my experience when we were getting into the Flex framework at work a couple of years ago. We thought the data binding was so magical, but once I started to work with it, I had a very good mental model of how the MXML/ActionScript compilers were doing their magic.

It was much more pleasurable to work with when it was no longer magical.

I'm not familiar with either framework, but at least I can understand the intent (if not mechanics) behind Knockout code. With Backbone, it's like reading a whole different language.