After using construct 3 from last 2.5 years I have learned few facts regarding it:-
1.) Offline thing rarely works:- suppose last time I was working on a project with 3 plugins (was online). If I run that project offline,it will work. But if I add another new plugin in offline mode, the preview screen will remain black untill I connect the internet back(I think that construct 3 does not load EVERYTHING during online mode. It only download that data which is currently needed. And when during offline mode if particular data is required which was not downloaded earlier then it shows a black screen). The plugin which I was talking are sprites,audio etc which are the basic components.
And even if offline thing works,"new project" button RARELY works. It will always show an error "failed to create a project"... Something like that. But to overcome that I have a blank project which I load and then work on it.
And suppose if construct 3 crashes due to any reason,there is 99 percent chances that next time when I load construct 3,I will be greeted by a huge construct 3 logo at the centre
Regarding desktop version, I don't have much experience.