MTA Recommendations with Freeside

[Eric Smoker]

Hello,

Pardon the newbieness of this message but I'm hoping a quick word from y'all could keep me from beating my head against the wall anymore.

I've got Freeside-1.4.0beta2 up and running (on the system described below). It's even talking With IC_Radius-0.18.1.

My problem is deciding on what MTA... to use. I've played with QMail, Postfix, vpopmail, courier... and all seem to leave me a little dry.

I'm migrating a single ISP with multiple virtuals from an M$ environment to Linux and I have free reign of what I can use. My users will only need POP and not IMAP. Does anyone have a recommendation of what MTA... is best supported by/easiest to use with freeside?

I don't have a problem with using the above mentioned programs, I'd just like some help in deciding on where to focus.

Any pearls (not perls:) about authentication methods would also be appreciated.

System:
  Freeside-1.4.0beta2
  Apache::ASP-2.3-11mdk
  Mandrake-8.2, Perl-5.601-7mdk, MySQL-3.23.47-5mdk
  DBI-1.28
  DBD-mysql-2.1017

Thanks,
Eric Smoker