I had been using Avast for about 6 years but just last year I gave up on it because the Adware they we pushing was annoying. They kept trying to push both Google Chrome and the Google Toolbar which I have no interest in which irritated me - alongside all the upgrade pop-ups were a nightmare.
I currently use Sophos Home and have it on quite a few machines alongside my Girlfriends' with it installed on - it seems to work fine and does the job - it is quite light also in comparison to others. It doesn't nag you to Upgrade or pushes any Adware or anything which is good in comparison to Avast.
I know Bitdefender free is also good but is also really basic - I haven't used Bitdefender in years though so can't say about how good it is now.
Sophos doesn't interfere with VM's which is also good but does block some Scammer Websites - which can be frustrating.