Hrm, I get mail in less than 1 second even through dspam, from most sources. But really there is no guarantee of delivery with email, there can be problems at the source, or destination to slow at any point. I know i can mail from hotmail and sometimes it is instant, and a few minutes later it takes 5 minutes, sending to multiple destinations so its not a destination server side. I have seen the same at other places I am just using that as an example.