I'm not exactly a top blogger myself, but I have researched this question before for myself, and I haven't found a straight answer. That is because there is none.
The success of your hubs depends on what you define as "success." Do you consider yourself successful if you have 1,000 views a day, or 500? Do you consider yourself successful if you've had a total of 100,000 views? Do you consider yourself successful if you're articles are high quality before considering views?
The reason there is no real answer is because if you consider Google successful, you can't consider Hubpages successful in comparison. It is all relative based on what your goals are.