That article is certainly a good read. But what I got out of it was that
deleted item retention is also fairly useless. If a mailbox is deleted
at all (via accident by an admin or on purpose because an employee
left), it is painful to restore it (restore entire server to a separate
box method).

Even if mail is deleted, it seems to me a lot of times it's lost
forever. As soon as you empty your deleted items folder (something users
do all the time), you can no longer retrieve that email. That makes it
pretty easy to still make individual mail restores a desirable feature.

I've never heard of the IBM Content Manager. Anyone have any experience
with what it is and how it helps in this case?

So all in all the only reason one might argue the TDP for Exchange is
better then the Veritas solution is performance in restores and backups.
Does anyone have real numbers on how much better it is in this case?

I've found this argument to be pretty weak amongst customers chosing
between Veritas and TSM as a backup solution. Exchange always seems to
be an important piece influencing their decision and they would gladly
give up performance and gain the higher level of granularity.