Well *I* like him. I'd just like him a lot more if Hugo didn't keep directly contradicting his personality traits. Marius is still one of my favourites because he's such a hopeless loser who's such a hopeless loser that he doesn't even realize that he is, in fact, a hopeless loser, and I find that endearing.
Yeah, in response to what Ulkis said about Marjolras, it was a stirring moment when Marius came up to the barricade and yelled, "KAY, WELL, IF Y'ALL DON'T SIMMER DOWN, I'M BLOWIN' UP THIS JOINT, YA HEAR?" Well, not those exact words, but you know what I mean. Marius is not the type of person to do anything bold (not that he's not brave, just not... bold), so this is his finest moment. If Marius were a total Gary-Stu, it wouldn't come as a surprise that he'd do something like this, because that's What A Man Does, or something.
I didn't hate Marius when he told Jean to go away-- after all, that was really what Jean wanted (even if his heart told him otherwise), and it was the sensible thing to do. And I thought it was really funny when he was doing such passive things to keep him away as not lighting the fire and moving the armchair farther away. That's exactly the sort of means Marius would take... just like throwing the paper into the Gorbeau house with Éponine's note on it, and just like his way of stalking Cosette; doing everything in an indirect, sneaky way.
One thing that I think is well-written about Marius is the way he treats different people, well, differently, just like real people do. A lot of book characters are always nice or always mean or always joking, or what have you. The way Marius treats Gillenormand is different from how he treats Cosette, which is different from how he treats Éponine, which is different from how he treats Valjean, which is different from how he treats Courfeyrac, which is different from how he treats Mabeuf. Marius is a more three-dimensional person than that.
In closing-- my very favourite Marius scene in the book is (in the Fahnestock-MacAfee translation):
He raised his eyes, loked straight at his grandfather, and cried in a thundering voice, "Down with the Bourbons, and that great hog Louis XVIII!" Louis XVIII had been dead for four years, but that made no difference to him.
CLASSIC MARIUS. Incidentally, my younger brother (who has only seen the musical) thinks Marius is hilarious and has a special nickname for him-- Emcee Pontmercy, or MC MP.
I am playing the Queen of France right now in a play. Try not to decapitate me.