[Art from H+FJ news page]
The powerhouse team of Hoefler and Frere-Jones took the classic slab serif look of Clarendon and improved it. They took it to the next level. They knocked it out of the park. They polished a diamond. (Okay, enough with the analogies!)
With Sentinel, they added weights and italics to create an infinitely usable slab family that will quickly replace Clarendon in my permanent font load. Thank you, H+FJ! Thank you thank you thank you!