This was a very long awaited extension which now made it to production. I have some experience in setting up linux mailservers - there are a lot of configuration parameters to take into consideration! SInce there are a many flavors of mx- servers there is always a chance that something goes wrong.
In my tests I found the DMXzone Mailer so simple to use that I could hardly believe it. A great extra is the possibility to send forms via SSL (Secure Socket Layer). I had some issues in the beginning which turned out to be mistakes on my side, e.g. port numbers ...
Pricing is OK, although I miss an extra discount for long-term clients who had purchased Smart-Mailer before and needed an upgrade; alas, Smart Mailer was extremely outdated.
The concept of integrating DMXzone Mailer into the "steps" model of "Server Actions" makes it very versatile and easy to combine with a lot of other extensions. I did not try the mass-mailer function yet. If it can be used, we need a delay function in order not to put our mailservers to black-lists. But as mentioned, I did not try it yet.
DMXzone Mailer is another great extension which will probably be used on every and each website with a feedback-form - from now on.