AVG Linkscanner will work with SA, I think it's good to keep them both. If one failed to 'rate' properly while the other rates a link as bad... that will help a user to decide (not to click).
Now that AVG 8 has the Link Scanner is McAfee SiteAdvisor still viable or even needed. I am seeing both of these rating sites/links when doing a Google search.
Looking for comments or thoughts from anyone experiencing this.