The newest version of XWall supports SURBL.

I haven't used or tested XWall, but it's certainly reasonably priced and it seems to be well-liked by the folks who do use it. (It also has a ton of non-spam-related features, including the ability to strip TNEF attachments and use POPbeamer).

I haven't used or tested XWall, but it's certainly reasonably priced and it seems to be well-liked by the folks who do use it. (It also has a ton of non-spam-related features, including the ability to strip TNEF attachments and use POPbeamer).