I've used Avast! for about two years on two machines, and love it. However, "upgrading" to the security suite on my Windows XP machine was good, but on Windows 7 machine was a disaster. While I couldn't run Outlook or normal Windows, I was able to back up to my external hard drives.
After uninstalling the Suite, I downloaded (and paid for) the Pro version like I had, and my Windows 7 machine is running just perfect.
After installing the Security Suite three times without success, I think I'll stick with Pro. So, Sunday night I spend $64.95 (for two machines and for two years) and Tuesday night I spent $34.95 for one machine, one year. Since I only have two machines, Avast! is not a terribly good deal for the money. :'(