Nodewebkit seems to work great as an exporter without any noticeable problems. Or am I wrong?
With ios8 & Android L, phonegap should solve all export problems on these 2 platforms.
As far as I know the WiiU export works quite well too
I dont think this is relevant in as much as they are still 3rd party options which can and do fail and which Scirra have no control over.
As i have stated before, i like C2 but i have also been seriously thinking about a move to Unity.