EAC is compatible with nearly all IDE and SCSI drives. Plextools advanced DEA is only available on Plextor drives.
EAC detects errors relying either on C2 infos returned by the drive, not very reliable, or by reading twice the same range, and checking that both reads are correct.
Plextools detects errors using C2 only, but it seems more accurate than EAC, at least with the recent Plextor burners (old Plextor drives are reported unreliable even with Plextools).
So, for recent Plextor burners, Plextools wins. For anything else, EAC wins.
EAC corrects error rereading bad ranges in bunches of 16 passes. If the same info comes more than 8 times, it is considered good.
Plextools rereads also the bad range, but it uses C2 to detect exactly the wrong data. Then it keeps any good data from any reading, and reconstructs the range using all the good data available from all the readings.
So, with recent Plextor burners, Plextools reduces EAC to pulp, with anything else… there is only EAC left.
Among the pseudo competitors :
Feurio : count the number of errors, but does not correct them
CDP32 : shareware : internally detects and corrects errors, but does not tell the user if did so
CDex full paranoia : detects about 100 times less errors than EAC, Feurio, or Plextools : http://www.hydrogenaudio.org/index.php?act=ST&f=20&t=3164