I find this is the hardest thing to sell among potential customers who
are considering both platforms (TSM vs Veritas). The reason tends to be
that Veritas's hotbackup solution will do a higher level of granularity
in restores - something companies in our experience definetly prefer.
Being able to restore a mailbox seems to weigh heavily in favor of
Veritas - or at least that's been my experience.

Now I know some of the arguments against it. E.g. it's not officially
supported my Microsoft and therefore if Microsoft makes a change to the
backup API or to Exchange, it could break their hot backups altogether.
This argument I find is of limited use because most companies who've
been using it have never experienced this problem and can easily argue
right back that Veritas will quickly patch the product such that it does
work.

One of the arguments regarding mailbox restores is also to use
Microsoft's deleted retention parameter so that the exchange server
holds onto deleted messages for a period of time before officially
purging them. That way they are recoverable without having to do a
restore of the server. My understanding of this feature though is to do
a mailbox recovery, it is still very painful and involves another
exchange server? I would love it if someone more knowledgable could give
me the low-down on how the deleted retention actually works when a mail
or mailbox needs to be recovered once it was deleted. How do you go
about recovering them?

Another argument is the speed of backups and restores. My understanding
is Veritas's hotback up much slower to do backups and restore. However
I've never seen any numbers nor have I had the opportunity to test this
myself. Exactly how big a difference is this? Does anyone have any real
tests or numbers or is this also a fairly week argument?

Thanks for the help!