Aurelia is a new framework by Durandal creator Rob Eisenberg (which helps credibility-wise).
It uses an interesting combination of technologies/techniques:
jspm is currently based on Traceur, support for 6to5 is work in progress. Quoting Eisenberg on how Aurelia combines 6to5 and jspm:
There is work on system.js currently to decouple it from traceur and allow the use of 6to5 instead. Note that it only loads traceur if you are feeding it actual es6 code that hasn’t been transpiled. Since aurelia is transpiled and the skeleton is set up to use 6to5…system.js actually never loads traceur and it never comes into play.
I haven’t used Aurelia, yet. Opinions welcome.