I have one, but the only thing I've ever cooked in it is rice. I think my little sis has done steel cut in hers, but this may have come up in conversation once five years ago, and my memory is fuzzy . . .
I use a small thermos for my oats when I don't have time to stand over a stove during the week. Can't stand instant. I use rolled oats here, but I am also a fan of steel cut, which I have not tried in the thermos as someone else did above.
Night before: 1/4 cu. rolled oats plus a bit of brown sugar, chopped walnuts, or flax seed, or whatever other dry ingredients I'm in the mood for, and maybe a pinch of sea salt.
Morning: fill with hot water from the thermal pot (really cool gadget that boils water then keeps it at 203 degrees -- available at any asian grocery store), and stir in a pat of butter. Seal thermos and put in pannier.
My commute is about half an hour, so oatmeal is ready by the time I get to work. I sometimes add a little bit of milk when I get there.