IMHO, there is no "best antivirus", every AV has their pros and cons, but every vendor offers different package for their product. The more expensive AV package means more protection for your PC, so if you want a better protection for your pc, then subscribe one..
Generally, AV vendors at least offers 3 package (some vendors offer more) of their product
package one: Free antivirus offers basic antivirus, mostly it's free such Avira
package two: Premium package, in addition from 1st package offers with extensive database, updates available more often than package one, some comes with extra feature such anti phishing and anti spam
package three: Internet suite, in addition from 2nd package comes with firewall, and offers with a pile of features such online backup, children monitoring, online support from IT experts etc
I suggest you use AV from big vendors such norton, avira, eset, etc