There are many different review sites and many different opinions... I recently saw in the current PCWorld Magazine a rating of free antiviruses ... I have to say I think its pretty accurate ... Not sure if they rated AVG... but if it was (the ratings were 1 to 5 ... best to worst) than AVG would be #6 (in otherwards, not even on the list)
1) Avast - I have to say on my 8year old laptop it was really sluggish but on my @ 1 and 1/2 year old Toshiba with Windows7, it is a-ok .... Very Good Detection Too
2) Avira - This is what I have on my old laptop and what I had (Trying Avast on my new Toshiba ATM) on my new PC before trying Avast.... I love Avira and even if I am using Avast ... I still recommend Avira 100% ... Detection only slightly behind Avast ... they deducted "points" for the fact they like Avast's Interface better
3) MS SE - I have to say I dont trust MS, but I have to given in and say all the reviews are very positive .. I dont like how it forces you to have windows updates on "download and install automatically" .. or right out of the "box"/"gate"/whatever .. I had to install 60MB of updates ON top of the I think it was 12MB for the Antivirus itself ... but for newbies that really dont like Avast, or Avira for whatever reason ... It's a decent choice.. with the exception of one test that rated 50% detection and Avira rated 70%, MS SE is on par with Avira Detection wise .... Did MS finally get something right?... They slim down there database and let you change the WIndows Update settings when MS SE is install... I'd say 100% yes
4) Panda - Cant remember too much about this 'review"
5) Comodo's AV - Not as good as any of the others (not counting ... POSSIBLY AVG), but "fair detection"
JUST REMEMBER Spybot (although not as good anyway as it use to be) and Malwarebytes (my #1 "must have" Windows Suggestion) are malware/spyware scanners and not really ment to be full blown antiviruses... just FYI
-Xmetalfanx
PS - for whatever reason if you feel you want to stay away from the good freeware AV's NOD's Eset32 is one of the few I would recommend (non-freeware)