4
Is this better then windows defender that worth the installation? (I know this is a avast forum but i would apreciate some opinions)
Some like avast others are happy with defender, your computer so your choice ;)

https://www.av-comparatives.org/

https://www.av-test.org/en/

No security program have 100% detection or zero false positives
No security program are at top of these tests all the time, the world of malware is not static so when something changes in the world of malware then AV vendors may need to do changes