IMHO, the reason Wuala is not popular (certainly the reason I dropped it), is:
- Its bloated and slow Java swing client app.
- It's buggy as hell, using the dokan integration MD5s of uploaded files do not match often. Using the java client directly works OK, but it doesn't exactly inspire confidence.
- Really poor integration with the OS (it wanted to install a kernel mode driver to create a filesystem mapping.)
- The inability due to its cryptree encryption protocols to do any kind of delta-upload.
- It had a bizarre notion of permissions, for example, there is no way to hide from the public which groups one is in.
- No android client
- Poor website, impossible to use on a mobile web-browser
Much prefer the alternatives, like Dropbox, SugarSync mostly these days. Wuala seems like it is ideal for uploading backups and other rarely changing files, and combined with the ability to get 100GB free (almost) storage this is what I think it should be used for. Certainly nothing involving rapid change or collaboration.
EDIT: Bullet point formatting syntax?