Some notes from a Mac OS X perspective:
http://www.wuala.com/grahamperrin/public/2009/04/11/wuala.png for a screen shot of Wuala beta (133) on Mac OS X.
http://www.wuala.com/grahamperrin/public/2009/04/11/wuala-nfs-finder.png for a Finder view of things; Wuala is presented as a volume.
http://www.wuala.com/grahamperrin/public/2009/04/11/wuala-contextual.png shows a contextual menu for a PNG in Wuala. When I realised how well things are integrated, my jaw dropped. I was truly amazed.
Uses of Java, nfs etc. seem to be excellent.
I could wish for:
* Wuala service to support extended attributes
* the Wuala application to be more refined
* an easier way to share/publish thumbnails of images
- but these things are not show-stoppers.
Summary: best in class! A winner!