Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Third-person: Cynical, Outraged, Hard; First-person: Curious, Wide-Eyed, Empathetic, Soft
The tones of the two narrators are complete opposites. The third-person narrator doesn't cut any slack to anyone, is quick to point fingers, and generally sounds like he hates the world he is forced to describe. Meanwhile, Esther tries as hard as possible to find the good in everyone – or at least to try to understand their point of view. Esther is naïve, which makes her sound constantly surprised, and she is naturally reasonably intelligent, which makes her curious to understand the world around her.
The third person is always busting out with some political message, as in this passage about Jo's death:
Dead, your Majesty. Dead, my lords and gentlemen. Dead, right reverends and wrong reverends of every order. Dead, men and women, born with heavenly compassion in your hearts. And dying thus around us every day. (47.140)
This is written in the style of someone testifying before Parliament (that's why he's addressing his Majesty the king, the lords of the House of the Lords, and the gentlemen of the House of Commons). Jo is the evidence, and we are all the defendants, being accused of the crime of not giving a red cent. And if that weren't enough, the passage switches by busting our chops not just about our civic duties, but about our religious obligations. If we have the ability to be compassionate, then why the heck aren't we out there doing something about the Jo-like miserables?
Meanwhile, here's Esther describing Richard's death:
A smile irradiated his face as she bent to kiss him. He slowly laid his face down upon her bosom, drew his arms closer round her neck, and with one parting sob began the world. Not this world, oh, not this! The world that sets this right. (65.59)
Even though there's plenty to get political about here – after all, it was the Chancery Court system that killed Richard, Esther stays pretty clear of that stuff. No, all we get here is feelings, feelings, feelings. Richard smiles, hugs, and cries. Ada kisses. Even when religion is brought in, it's not a stick to beat us with for being such awful people, but instead a carrot to give us hope that stuff will be better in the next life.