I am needing recommendations (quickly) for a stable MX host. My client wishes to use MS Outlook via pop3 and needs excellent SPAM reduction without verification emails being sent out for whitelisting.

I need a host with an exceptional amount of uptime and speed, with a reasonable amount of data storage for email. Again, this is only email hosting and not www.

I've had him on cPanel and Plesk servers and things just kept going wrong for him, so I'm seeking advice from the community. I run a stable service, but this guy's somewhat high maintanence