I find its mostly Toronto Star fans who carp about how right-leaning G&M is. In my travels across the country, I have found G&M to be the newspaper that best reflects the attitudes of Canadians across the country. The Star is really a Torontonian pecularity, and if the comments are any reflection of the readership, the newspaper might not reflect the views of its readers necessarily. Certainly, I don't think the Star's editorial line reflects the attitudes of most suburbanites. We saw solid evidence of this fact during the Harris years.
The only reason the Star has good circulation is because of the fact that it is a local newspaper in Canada's largest city which offers excellent coverage about GTA issues while providing adequate coverage of national and international news. It also provides significantly better coverage of things like sports than the national dailies. That's why the Star sells. That and their drug dealer type marketing techniques (free papers to schools and colleges/universities) help build a loyal readership.
I am fairly sure outside of the GTA and a tad beyond, that the Star is probably not widely read. In contrast, the New York Times is quite a different standard of journalism. They are really a national daily with excellent coverage of New York. The Star would have a long way to go till they achieved that standard.