no.  not at all.  i could post links to the sites of illustrators who have been in the industry for years, do beautiful work, and have sites that are awful and unusable.   or i could show you links to portfolios i think are really strong and effective, but the work in them isn't very remarkable.  the abilitiy to be a good illustrator and the ability to make a good portfolio are totally different things.  and if what you want is to look at people's work for comparison or examples, then what you want is the former.  if what you want is to think about how best to present your own work, what you want is the latter.