Originally posted by: Goi
Is there any difference between the free Antivir Personal and the commercial Antivir Premium?
Yes. One of the big ones is that the commercial version's real-time scanner can be configured to "nuke first, ask questions later," wheras the free version's real-time scanner always asks the user what to do. This is one reason I'd gladly pay $27/year for the Premium version for my parents' computer, because they'd be clueless as to what they ought to do with a malware alert
The commercial version also scans email
en route instead of waiting for you to try to open a malicious attachment. IIRC it can arbitrarily pre-nuke suspicious attachments by filetype (and again, it can do this without asking the user, making this another feature that's desirable for my parents' system). It can be configured to scan outbound email.
There's also a separate "Web" module on the commercial version, with its own suite of settings. If you'd like to max out the heuristics
only on stuff running in the Web browser, and run medium heuristics for other real-time protection, it can do that.
How do they compare with Kaspersky 2009 in terms of coverage and speed/responsiveness?
Kaspersky has proactive-defense features in addition to signature-based and heuristic defenses, and adds a vulnerability checkup that'll look for exploitable versions of stuff like QuickTime, RealPlayer, Flash Player, Adobe Reader, etc. Kaspersky also allows you to pre-configure what's going to happen to detected malware (I always go for "shoot first, tell me afterwards").
As far as speed/responsiveness, you can download trial versions of Avira's Premium verions and Kaspersky's products and try them out for free if you want.