NOrton & Macafee get installed on almost everything to get unsuspecting people who just install it and never think to upgrade again. Parents PC came with Macaphee 6 years ago and only just got rid of it last year.
Avast? App spends half its time trying to sell you things. I had it up until December when I got sick of them begging for money and I was using their security Suite, I couldn't really pay them much more.
can't go wrong with any of these but Avast is just above Defender, and everything else above it:
http://www.tomsguide.com/us/best-antivirus,review-2588-5.html
I use Bitdefender as it asks me no questions, it just does it job and pretty well.