Please don't cherry-pick. If you reread my response, you will note that I
recommended a SMART report and a surface scan.
A drive with 2000 reallocated sectors, say, can still produce an error-free
surface scan (SMART extended/long test), but would you want to buy it?
Neither SeaTools nor Data LifeGuard report the actual number of bad sectors
(Seagate's SeaChest does). SeaTools simply awards PASS or FAIL.
A drive that "stutters" when reading difficult sectors, or which has a
"weak" head, may still pass the scan test, but its performance will suffer.
Would you want to buy such a drive? Third party scan software will identify
these sectors, but the manufacturers' tools will not.
Seagate's SeaTools is really only useful when you need a "test code" for
warranty purposes. The test code is an encrypted number which is generated
from the drive's serial number and the number of the failing test. Even if
Seagate is unable to reproduce the failure, the test code is your proof
that a failure did occur in the past.