Avira or avast? İf answer is avast, why avast is free?
why ask this question here?? this is avast forum…and only answer given here will be avast!
My testimony: avast really protected me like a superman against a highly infected USB stick…and plus avast has so many additional line of protection which really came to me handy in danger times. 
Avast! also uses GMER which is in built in it…which is really awesome and detects all the varients of rootkits and also in some cases removes MBR rootkits that other AV’s fail upon to do so…
Because where lucky
There is no perfect antivirus program,avast may miss something that avira don’t and the other way around.
But from personal experience,I prefer avast and while I was searching for free antivirus program,avast home had all of my requirements for antivirus software and as a bonus,it is free
BTW if it’s not free don’t always mean better.
There are plenty of free programs that are better than similar but not free programs.
By using your logic, how could Avara be better since it is free? :
i also say avast is better then avira. avast using low ram. have high detection rate ( avira also have that but also have high false threat) fast scanning speed, self protection avira does not have this. sandbox another thing avira does not have. + avast one of the best support forums there is. you ask a question and you get help in a few a hours.
the list can go one even more but because of this thinks i use avast instead of avira.
i have used avira in the past but got tired of the nag screen of upgrading to full version when i used the free one because of this i chanced to avast. i ahev been using avast for roughly two/ three years and will not chance. sense the 4.8 version…
Having used both I will say Avast is lighter on system resources in most cases, obviously there are always exceptions. It uses multiple layers of defense and is highly configurable to work best for your individual needs, not to say that Avira can’t be but I like the offered configurations and lack of an updater nag screen with Avast without a doubt. The tendency of Avira to report false positives has been an issue for many years and while this can happen with any security solution it does not seem to happen as often with Avast, assuming something odd is there you have one of the multiple layers in the sandboxing feature of Avast to help protect you as well as the many different shields which can protect in a multitude of ways. If you want to see a side-by-side a quick Google search will yield some results worth looking over. One such example can be found here: http://antivirus-software.findthebest.com/compare/45-152/2012-Avast-Free-Antivirus-vs-2012-Avira-Free-Antivirus as well as here (with a nifty chart that helps) http://dottech.org/freeware-reviews/14151/
Both of these are a bit older and with Avast now in the Ver7 range they have only improved so use what works for you and that you like best but I always suggest Avast before any other free offering and I also use it myself. 8)
Use http://www.av-comparatives.org for some comparison data. Protection and performance are benchmarked there.
AV Comp is great, for easy reference: http://www.av-comparatives.org/comparatives-test-reports
Maybe it is overzealous from me, but I think AV Comparatives does not allow to post part of the results/tests. We need just to post a link.
Edited it just in case but I did not see anything stating as such on the home page.
It is not allowed to offer the results in any form in full or in parts on a website for download,or to take parts of it into own tests or to use the data ulterior without a written permission of the management board of AV-Comparatives.
About us page, would have figured if they wanted everyone to know it might be obvious on the main page, think I recall this from a few years ago now that I think of it.
HI would like to give some reasons why I have avast free. I like the avast forum community is very helpful and if you have a question or concern someone will answer you with in an hour or so and they will keep helping you until you have got a solution that works for your problem/ issue or concern. Avast antivirus / free found a couple viruses on my home computer and put them in the virus chest for me so they could not do any damage at all, Avast does not take up a lot of room on my computer, Avast has lots of layers of protection, and I have not had any trouble registering avast free ever on my computer and Avast free is easy to use and configure to your needs. and avast blocks trojans, malware and viruses from getting on to your computer. Overall I have used avast free for about five years and it has not let me down it has come through with flying colours.
I hope in the end you choose a good antivirus whether free or paid and I hope you choose avast in the end.
have a great day