I am particularly struck by the way in the opening chapters we get a fantastically balanced view of Emma - her good and bad points

For example- we see her comforting her father over the loss of Miss Taylor "Emma spared no exertions to maintain this happier flow of ideas, and hoped, by the help of backgammon, to get her father tolerably through the evening" (1) despite the fact that she herself was suffering on the same account
"How was she to bear the change? -- It was true that her friend was going only half a mile from them; but Emma was aware that great must be the difference between a Mrs. Weston only half a mile from them, and a Miss Taylor in the house; and with all her advantages, natural and domestic, she was now in great danger of suffering from intellectual solitude." (1)
She really does diplay remarkable selflessness in her attitude towards her father.
But then of course we have her snobbery towards Mr. Martin
"a young farmer, whether on horseback or on foot, is the very last sort of person to raise my curiosity. The yeomanry are precisely the order of people with whom I feel I can have nothing to do." (4)
I think we are given all the clues we need to understand that this is a character who is capable of both great goodness and some less laudable characteristics.