Anyone ever used data recovery software for CDs & DVDs?

Here's the scenario: I have two DVDs here which someone 'wrote' (or thought he did) with "Verify Written Data" turned off. Well, when I got there, I recognized the DVDs as being the same brand I had the same problem with several months back. The program would chug along as though it were writing data to the disk; but, when it went verify, it would fail.

It turned out the disk was actually blank. Looking at the bottom side of the disk, one could see that it looked like it had data on it; but, opening it in Windows Explorer showed a drive letter and an empty window.

I would like to hear some suggestions. I would especially like to hear from anyone who has used any of those data recovery programs I have heard and read about for CDs and DVDs.

By the way, I've tried the DVDs in two other readers with the same result. And, his writer does write readable disks on brands other than Verbatim.