I also tried the software, and it proved rather useful, a bunch of times. And it DID recover physically bad sectors, as mentioned
here.
The only drawback might be the recovery time. It took me around 2 days to recover a 40Gb Maxtor HDD. This can be annoying if you have a huge Drive.
Nonetheless, it wouldn't be a really safe solution, as the recovered sectors have a slightly reduced lifetime, and are still threatened of premature failure. You should probably check out your HDD Health, using any S.M.A.R.T. featured tool (i usually rely on
SpeedFan's In-Depth Analysis). You will want to replace it ASAP, if it reports a critical HDD status. =/
Jam it back in, in the dark.