In responding to this and to Greybeard's earlier reply to me (thanks!) I believe it was Unity which put me off top edge menus. The top limit to mouse movement (= less aiming required) is logical but DrXym's point about multiple small windows and large mouse movements was a stopper for me.
I wonder how much of this is simply 30 years of being exposed to menus-on-windows? Were the tests that Mr Tognazzini describes performed on naive users or with people who have used one or the other approach for years? I suspect the results might be different for different groups.
I can't help feeling that the biggest barrier to adoption of a new 'better' UI is simply familiarity with the old one - for example, I find the MS ribbon to be a largely unusable mess. But I am aware I am an old fogey; hell I even write in C so what do I know?
Nonetheless, I shall have a play with this project. You never know - I might like it!