Avast is a fine AV solution protection wise but I prefer to use built-in Windows tools as much as I can to avoid incompatibilities (mostly the troubleshooting part).
Became a fan of AVG this last month or so, finds it runs much smoother on my other half's newish lappy (than KIS) & speed increase noticed by her - I have AVG on this PC built back in May last year, just gave AVG and AVAST a quick try & I really liked it so left it on, I expected to dislike it frankly - Prefer the UI of AVG to AVAST but essentially the same product - Thanks to test by McMcBrad.