We tried it; I was the guinea pig.
Every time we had to install Windows updates on the master image, my personal vDisk broke, and it took an act of $DEITY to get it working again.
The last time it happened was just before the Citrix conference, so our guy took the details with him. Turns out he knows more about how Personal vDisk works than their experts, as they didn't even know of the solutions we had used successfully in the past. They had absolutely no answers.
It still hasn't been fixed. I've moved on. We may reconsider if they get their act together.