volvie-
Why your preference for AVG over avast (also free)?
It isn’t a preference; it’s a recommendation based on personal use. AVG is one I use, so I can recommend it first-hand. Avast is also highly rated (it has slightly higher user ratings on the CNET page I referenced), but I’ve never used it.
Can you comment on avast?
Not based on my own experience, but it’s highly rated by both pros and users.
And how they compare to the commercial anti-virus programs (Norton, McAfee).
For virus-checking, I think they’re comparable.
Is there any benefit using a commercial program for the anti-spyware or firewall (compared to the free programs)?
-Symantec (Norton), McAfee, and ZoneLabs commercial programs include antivirus, anti-spyware and firewall all in one.
-In my experience, they also have a higher level of customer support than the free programs do.
For the above two reasons, they may be simpler to use, and a better choice for someone who isn’t interested in potchking with multiple programs, or doesn’t know much about PCs. Also, some vendors will throw in a subscription to one of the above packages when you buy a new computer.
As far as protecting your computer, I think you can do just fine with the free programs.