Most excellent logging/intelligence you'll find
What do you like best?
MDaemon is filled to the brim with features, true, but my favourite aspect of it is the logging. Whatever is happening on your mail server, you'll be able to trace exactly what is going on, when, and where. Nobody likes pouring through thousands of lines of log files, but all mail administrators know that it's part of the job, and you'd rather have all the data there ready for you when you need it. MDaemon gives you the intel you need.
What do you dislike?
Some of its components can be a tad unstable at times (i.e., content filter engine getting stuck at 99% CPU and requiring an application restart), but on a server that's up 24/7, this happens seldom and is only a minor annoyance. Also, we have had slight issues with one of the antivirus engines the product employs (it uses two concurrently). The above problems have been relatively easy to deal with, and MDaemon's support was very helpful.
Recommendations to others considering the product:
Even if you don't use it for full-blown mailbox access, using it as a perimeter/edge gateway in concert with another product like Microsoft Exchange is excellent.
What problems are you solving with the product? What benefits have you realized?
Again, the intelligence factor is critical. Sometimes clients need to know where their email is going or why their clients claim they haven't received something. Being able to tell my clients with absolute certainty that the message reached the destination and the problem isn't on their end is wonderful and gives them confidence in their systems and our support. The logging is second to none.
