I just don't trust it, and iDisk never worked reliably or quickly compared to Dropbox or Google Drive. iDisk would often crash the Finder.
I forgot all about that. That was so frustrating when I was paying for MobileMe and extra iDisk storage to send clients large files.
The progress bar never progressed correctly either when copying files. It would often just hang at a certain point. Since my ISP's upload speeds were a fraction of the download speeds, uploading a large file was a huge risk and often resulted in failed uploads and sometimes hours wasted. If the upload failed, it would often give the spinning beach ball of death with the Finder unresponsive for a few minutes before popping up an error message. It was sometimes better to just upload files through Safari's iDisk page. Hopefully they did something to address this, otherwise I'm sticking with Dropbox.