280 karma · joined September 2, 2012
I'm not really seeing the size advantage here. All of the mentioned frameworks are cached on popular CDN's and I just don't think you're really getting much of a win out of creating your own, smaller files.
Also, I'm always wary of companies that want to re-invent the wheel as opposed to using open-sourced, well-documented projects. If I start at your company and you use Backbone, not only is there a good chance I can come in with a good understanding of your code -- but I can easily check on Google for any questions I have. If I start at a company that has built their own, closed-source, custom JS framework -- I'll have to ask internally every time I have trouble figuring something out.
It may be necessary for your product, but to me it always raises a flag when people create their own proprietary version of something that already has been done.
Anyway, a great read for sure!