Concierge.com's insider take:

Housed in a three-story mansion built in 1903 by the wealthy Allemand family, Milión encompasses three high-ceilinged dining rooms, two exterior terraces, and a warren of candlelit nooks. Beautiful porteños of all ages come to preen and flirt on the sweeping marble steps, or wander idly with a cocktail through a creeper-draped garden dominated by a towering loquat tree. The Allemands' piano, family portraits, marble fireplaces, and wall ornamentation remain intact, yet Milión is far from stuffy: Waiters are wont to wear T-shirts and dreadlocks, yet they display impeccable manners. An impressive cocktail list includes hard-to-find single malts Caol Ila and Glen Ord, making the first-floor bar popular with louche night owls, but the real attraction is the standout cuisine: sweetbreads with salad and quail eggs, tuna steak dripping with lime, and a lamb tenderloin roasted with onions and wild rice.