AVG Anti-Virus 7.0 Email Server Edition

I have been kicking the tires of various anti-virus packages for my SBS computer. The folks at Trend-Micro are a favorite among the SBS consultants while I have a lot of experience using McAfee and Symantec on workstations. All the virus checkers appear to be good. In my opinion the primary entry point for viruses on my systems appears to be email. Since my spam checking software has identified all email containing viruses and deleted the email on the ISP, Symantec has not identified a virus in a long time. The email I receive into Exchange is virus checked at AT&T Worldnet. The email I receive off of Yahoo is virus checked by Symantec on my workstation. It may be checked at Yahoo, too. They haven't told me but I think it is part of some recent changes to their email system. So you are probably wondering why I am evaluating AVG if I am already covered. The reason is AVG is inexpensive($120 for two year license) and I needed a fileserver anti-virus checker. The comparable product from Trend-Micro would cost about $300 for two years. The cost of renewing my two existing Symantec licenses is about $15 year. I think there is a small advantage being covered by two different anti-virus checkers.