4.0 format vs. stand/diag

[apex!larrys at uunet.uu.net]

Is there any information on the relative merits of the OS resident 4.0
format and the standalone disk diag programs?  I have found some practical
differences, for example, that diag will format and surface analyze
faster, and that diag will come up when you're in a hurry.  Fortunately,
on a Sun-3, you can copy diag and other standalone programs into a
directory called /stand on the 4.0 system and still use diag when you are
in a hurry.

So are there any real technical advantages to format over diag -- or are
all the advantages in diag?