They all have an auto update geature as well as scanning scheduling. The main differences between all of the antivirus software out there are:
(1)..Footprint: Some and Norton is probably the worst offender like to fill the registry with codes and use a great deal of system memory to run while AVG is considerably smaller..
(2)..Ruleset: The other difference is the ruleset and updates. They both offer updates every other day to cover the latest threats so they are prettl well identical there.
(3)..Is one better than the other...? Thats all personal preference really. If you want a scanner that updates daily ( every single day) then loof at Bitdefender, Nod32, Kaspersky, panda or Sophos. They are the only ones currently updating on a daily basis.