I would say success of a Hub is determined by whether people are reaching your Hub when they use a search engine, and whether Google crawlers are finding it. Then you get traffic, exposure, etc. And this is determine to great extent on Keywords (words in the Hub which turn up in search engine search results). Of course, if not talking about traffic, then if a Hub is good in terms of quality, then that is what is significant. But I'm assuming this question is addressing the issue of traffic. I think Accolades are good though, because I think it indicates participation in the Hubpages community, which does affect Hubber score, which in turn affects whether Hubs are indexed in the search engines.