This question can be simply answered by stating that most Brazilians do find her unfit for presidency. Since more than 70% think her government is a bad one nowadays.

But political things in Brazil are never simple, since it's a country with multiple powerful parties, very complicate (and convoluted) relationship between the Three Powers, considerably young modern democracy (military dictatorship ended in the 80's and is a major hub of interested in the current geopolitical struggles (which is a thing that most Brazilians, right or left, keep forgetting about).

You can say that support to her through socioeconomic spheres change drastically, but saying poor and educated people support her, while rich and educated don't is an oversimplification. Support dynamics to Dilma is more similar to Obama than most Brazilians (conservative or liberal) would care to admit.
She indeed has a lot of support in volume from poor people, since she is a bastion of the social welfare programs that gained strength throughout her party's government (since former president Lula from 2002 to 2009). This population is indeed mostly motivated by the gigantic living standards leap they went through in the last decade (starvation was a serious grievance in the 90's).
But she also has a somewhat strong support from the middle class in the regions were most positively affected by the social welfare programs and growth/infrastructure incentives in the last decade (North and Northwest). There was a greater improvement there than the already rich South/Southeast where she faces the strongest opposition. But than again, migration of people below the poverty line in southern urban centers plummeted, which had a positive impact rarely approached in these regions.
Another social group that mostly supports her is the one made by most liberals and intellectuals, although they tend to do a lot of criticism towards her lack of political skill and resolution, they see her as a better alternative than her main opposition. Actually, the more you go up in social related education (sociology, journalism, anthropology, political sciences, etc), the more support you find for her.

On the other hand, the bulge of the South/Southwest population do believe she's not only incompetent but also corrupt. Most of the middle and upper classes would like to see her impeached tomorrow, even if that meant Brazil facing a downgrade in its investment rating due to political instability and a party that would assume the executive power is way deeper into the corruption scandals that hers. So yeah, you can say that there is a HUGE slice of the population that hates her to brink of having a considerable number asking for military coup.
Considering the higher education slice, among technical/financial oriented fields of education (engineers, business adm, MDs) are mostly against her. Which is a bit complicated since this population is strongly intertwined with the richest layer in Brazilan society.

...not to mention that the richest population in country that is social inequal and not far off from its recent dictatorship tends to be the most educated AND the most conservative at once.

So things are complicated... Support for her shifts in a layered onion fashion through Brazilian society. But the strangest thing about this dynamic is that most of the Brazilians that are against her use catchphrases and advocate on ideologies very similar to the anti-Obama movement in U.S., yet they identify themselves as democrats, sympathize with Obama and think of them selves as liberals (while they are only liberals I the economical sense, not the social one).