I used MailEnable to setup the company email. I want to say that is easy to setup and also easy to troubleshoot when you need to investigate if emails were successfully sent or not.
The maintenance is easy .third party smtp relay is also available and its very useful to integrate with Baraccuda for 100 % spam free.We can create Lists ,we can create Groups,We have Catch all Address ,Debug tools are simple .mostly its very cost efficiant.