Until Atom is written natively I don't think Sublime Text is going to have a serious competitor.
Electron and other Chromium wrappers are the new client-side JVM.
Visual Studio Code is based on JavaScript too and it's very fast. They even both use Electron, the JS-desktop-app core that the Atom guys open sourced separately.
Loading a 100MB text file is not really common, even among developers. Only logs and DB dumps are really that big.