Hi all ...I have recently tested Interspire Email Marketer with different mail servers like Exim , Smartermail , postfix , Atmail,Axigen,Exim ,FirstClass,HMailServer,IceWarp Mail Server,Ipswitch IMail Server,MagicMail,MailEnable,MDaemon Email Server for Windows,Port25, PostMaster,qmail,Sendmail, XMail, Zimbra,ZMailer and found that in more then 80 % mails are originated from IEM are going to spam , even if your ips have good reputation....and if you do not modify your email header.
While Power MTA is still leading the sending speed with multiple IPs ..... i have used 900 Ip simultaneously with a single Powermta installation and its grate .....At the same time PMTA works with multi-domain configuration with multiple smtp users ....this is also a grate feature.....
Let me know if that helps any one .....skype me if you need any more help ....keep shearing KB...