Absolutely none. Most of my fun comes from solving every problem myself and Subbania was started before such engines and libraries even existed.
However, I probably would recommend something like CraftyJS because it can help take some of the cross-platform troubles off of the developers' shoulders.
Hey, I'm the developer of CraftyJS and now the lead SDK engineer for Game Closure. I would love to talk further about the tech and potentially working together. You can reach me via twitter (@louisstow) or my gmail louisstow AT gmail.
However, I probably would recommend something like CraftyJS because it can help take some of the cross-platform troubles off of the developers' shoulders.