Well I can definitely answer some of these questions...

Our Config: (for exchange)
IBM PC Server 325 (handles all SQL and EXCH)
ADSM for NT 3.1.2.13
256meg of RAM
100mb Ethernet (ADSM)
18gig disk pool (Exchange only)

4 Exchange Servers:
IBM Netfinity 5500
Dual 450's
896meg of RAM
155mb ATM
50gig Exchange storage space provided by an EMC disk array


1.      Excellent quality, backups are always flawless and rather speedy.
(11-12gig an hour)
2.      Restoring a exchange database that is 14gig to a recovery server
takes approx. 1 hour 5 min.
3.      The backup and restore GUI is extremely easy to use, the Exchange
admin learned it in under 2 min.
4.      Configuration is somewhat clunky...  more steps than setting up the
regular client, but the same is true for SQL agent's that we use also
5.      No experience, sorry.

As far as I know exchange itself doesn't allow restore of signal mailboxes..

We have had to restore to a different server, and export the mailbox out to
a pst file and then import it into the production servers

I don't think logging method matters if you do full backups every night...
which we do, but we have our servers set to normal logging.  (and have
tested incrementals this way, and found no problems)

Please feel free to email me if you would like more information on our
setup.
WesLewison AT winn-dixie DOT com <mailto:WesLewison AT winn-dixie DOT com>