After all the hype on this board, I tried Cacio e Pepe last night (Sunday) and wasn't disappointed.
There are a few tables on street level, but the main dining room is several steps down from the street, with a low ceiling that thankfully makes it seem homey rather than claustrophobic. It wasn't very crowded when we went around 9:30; there were several large groups there for birthdays, some of them eating family-style, but the noise level wasn't noticeably loud.
My date started with mussels skewered and grilled over artichoke hearts. I'd never had mussels this way before, and I liked them; they were dusted in bread crumbs before being grilled, and hadn't lost their plumpness. I had the fennel & little nail mushrooms salad, which had a nice earthy flavor, dressed with olive oil and lemon that balanced it out.
My entree was the strange-sounding but improbably delicious rigatoni with quail ragu, truffles and blueberries. Again, good balance here -- of gamy and earthy and buttery and sweet. My date had the cornish hen, which had a fantastic red-wine vinegar glaze.
We had a bottle of organic Chianti which I liked but didn't love (but I'm not a necessarily a Chianti person).
Bill came to about $120 not including tip (and with a $40+ bottle of wine).