I would still go for a non-Beta release, just to make sure that the bugs are worked out. Remember that Beta still means, "Not Done Yet" and is for evaluation purposes. The same is true with Release Candidates. The current version is 6.0 in general release. I updated through the GUI from Avast 5.1 to 6.0, and it works fine.
Or you can wait a week or so, for this next general release build. I am not a fan of Beta's, unless you are a user who knows a lot about computers and is willing to possibly troubleshoot issues with the build.
My take would be either install the current general release of 6.0 now, or wait for the next general release of 6.0.xx.
Jack