I started running my own mail server recently and spam hasn't been much of a problem with postscreen + spamassassin (with pyzor and razor).
Also, if you are worried about deliverability of your own e-mail: worry less. I am running my mail server on a VPS and the only place I've had any trouble delivering mail to so far is hotmail. They were blocking my IP, so I requested that they investigate the block and it was removed within hours.
Dear x
Please note that your ticket number is in the subject line of this mail.
x.x.x.x
Note: Errors are unlikely, however, if an error is indicated, please resubmit the specific IP or IP range.
Thank you,
Outlook.com Deliverability Support
Please do not reply to this message as it is from an unattended mailbox.
Any replies to this email will not be responded to or forwarded.
This service is used for outgoing emails only and cannot respond to inquiries.
About an hour later I got another e-mail from them informing me that my IP address had been "conditionally mitigated", and I was then able to send e-mails to Hotmail.
Also, if you are worried about deliverability of your own e-mail: worry less. I am running my mail server on a VPS and the only place I've had any trouble delivering mail to so far is hotmail. They were blocking my IP, so I requested that they investigate the block and it was removed within hours.
It's really been a very pleasant experience.