Mike, you can still try out DreamHost for 91 days and see what they have to offer. They have a full money-back guarantee, so you have no risk.
About their spam filtering, here's my view on it:
Razor is per-mailbox but it is not very effective. I stopped using it a few months back because I switched to the new SpamAssassin-based "Junk Filter" solution.
The Junk Filter is not only SpamAssassin but extra code as well. This combination works extremely well for me -- I get about 0,2% junk mail now compared to earlier, and I used to get a lot.
The Junk Filter is turned on or off for a whole domain at a time (using the control panel), and can only be turned on if there is not a catch-all on the domain. Some people find this limitation bad but I don't mind; it's just a question of knowing your addresses and creating those that you need.
The Junk Filter settings are individual per mailbox and are controlled by logging into http://webmail2.dreamhost.com and going to Options. You can adjust a "tag" level that marks the message as spam but still puts it to your mailbox, and you can adjust a "catch" level that will put the message in a special quarantine folder. Getting these values right is not hard, and will help you to optimize your junk level according to what you actually receive.
The custom own-domain webmail does not show this Quarantine folder because the quarantine is actually on a separate mailserver, not part of your own mailbox. That's why you must use http://webmail2.dreamhost.com specifically to check and change your Junk Filter, but for all other mail tasks you can use your own-domain webmail or any mail client software.
I am extremely happy with DreamHost in general and also with the new Junk Filter. I suggest that you try it out and if you're not happy after 89 days you can always get your money back!
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