On a completely different note, I think this looks fantastic. There are so many javascript frameworks out there but none of them have really approached the cleanliness and simplicity of rails so I've been reluctant to pick them up - this is definitely the closest I have seen. I will give it a shot for sure - props to the authors on good work!
I agree - none of the other frameworks I've tried have felt right, but this looks like a great fit with Rails - we'll see if I feel the same way after using it though :)
One quick thing I noticed playing around creating a demo app - the generator seems to have generated some incorrect haml in the layout that it creates. First, it has "javascript:" instead of ":javascript" for the filter, and once that was fixed I noticed that I had to change 'window.preload' to 'window.joosy' to get things to work.