I really do not see the harm in trying it at least. If we be in the "church" of Avast!, AVG is not the devil, just a different denomination
Guess it could have some impact on browsing speed, in addition to the Web Shield. And I do not know exactly how Linkscanner works, but I know it "scans ahead of you" somehow, so you might run into a time Linkscanner detects something, but Avast! first detects Linkscanner, typical FP conflict. So it might not hurt to exclude the necessary processes/folders with the Avast! Web Shield/ File Shield to avoid that.