On demand scanner to complement NIS - Avira Antivir or MBAM?

Hello,

 

I've been using NIS2009 and 2010 for a while now. I've read about layered protection and so, have always had Avira Antivir Free as an on demand scanner (during installation, the real-time part can be deselected). I run scheduled scans using both NIS and AntiVir. 

 

On this forum, I do see that folks recommend running an on demand scanner to complement NIS. However, the recommended on demand scanner is always MBAM (but for the occasional SAS recommendation). The reason to pick MBAM has been that its scan engine complements NIS' scan engine nicely.

 

The reason I picked AntiVir a couple of years back (I do update it regularly) is that it usually has the highest detection rates in comparitive tests - yes it also has very high FP percentage, but, I can live with that, since it is just on-demand scanning.

 

So, my question is why is AntiVir never recommended on this forum as an on demand scanner? Is it because its scanning engine is like Norton's and not complementary like MBAM's? Is there any other reason?

 

I have MBAM free downloaded and ready to install (after wiping out AntiVir) based on the posts I read here. However, answers to my questions above will help reinforce my decision and make it a well-informed decision.

 

Thanks.