It was recommended by a CS grad who had a lot of experience with that sort of thing. Seemed to work well for what we needed it for. I've never used the Windows one El Joffrey suggested, but basically both should destroy most personal data (www.dban.org)

Having worked a bit with computer forensics, though, some info will not be erased unless the harddrive is shredded (i.e. can't be deleted by software). It would take a pretty knowledgeable person to get it, but still...May be safer to replace the hard drive if you plan to sell.

Just some thoughts from my experience.