Downside of dd is that it won't display the speed of the sectors being scanned. If you have for example 100 sectors with an access time of 1 sec then you may want to replace the drive anyway.
For this reason I always use MHDD, which displays access times. It can also check SMART status.
Search the forums for it, I believe I once some instructions for it.
This is not something of a hoax, it's true that an older version had a bug in it (A moth would be triggered, not a butterfly) which may cause the hard drive to break, but this has been fixed a long time ago. It is now considered to be quite safe.