We also like the AEC as contrast to hematoxylin but use DAB on occasion for
the following reason. I guess the question is WHY?? do they like it, the
way it looks?  and something they are used to??  

DAB is permanent, if they want to go back to the slides in future years,
this may be a choice.  It looks fine with nonoverstained hematoxylin.
Some people prefer the black enhanced DAB vs a brown unenhanced, you still
have choice here.  More sensitivity by DAB may mean further dilution of
antibody (one thing we found here).

There is a new red peroxidase chromogen, Vector NovaREd, on the market, that
will be like DAB for sensitivity and longevity, a possible good replacement
for AEC.  Worth a try, from Vector, hopefully Ventana will let you try it
out.

Gayle Callis