I've eaten at all 5 restaurants recently, and of the 5, Blue Hill is my favorite. The food at Blue Hill is very nice high quality, and cooked so that the flavors of the food shine. The potato ravioli with leek sauce as appetizer was delicious, as was the lamb with curried chickpeas as the main dish. The appetizer of poached foie gras with root vegetables was good (but not "delicious" as the above mentioned dishes), as was the poached duck breast. Desserts we tried were a chocolate bread pudding (I think), and a passion fruit souffle with passion fruit ice cream, both good and satisfying, but not spectacular.
Tamarind is my favorite indian restaurant, wonderful service, and good clean tasting food (no rancid oils). Last year we went on a short-term indian food binge, but noticed that at many of the restaurants we ended up with headaches, sometimes while still in the restaurants. At Tamarind, that has never happened.
The Biltmore Room is very similar in quality of food to Blue Hill, but with many more spices, an asian-fusion theme, sometimes with alot of hot spiciness that can overwhelm the flavor of the food itself. Very good service, a very comfortable room, and remarkably similar desserts to Blue Hill, but the passion fruit souffle at The Biltmore was much more interesting with canidied ginger on top and a side of coconut (I think) ice cream , making a nice contrast of flavors and textures.
We tried Hearth last night, and among the restaurants mentioned thus far, was our least favorite, although the food was good, as was the service. For appetizers, we had the torchon of foie gras, a decently sized piece, but only with 4 small pieces of brioche bread,and the foie gras was not particularly flavorful. The calamari salad with arugula was ok, but had a bit too much salt and the calamari was a little tough. The Sunday night pasta special was delicious with 2 veal-ricotta meatballs and 3 ricotta ravioli. The oft-mentioned (on this message board) monkfish osso bucco was OK, but nothing special. A side of gnocchi was served with (too much) coarse salt and parmesan cheese. The recommended 2 apple cider doughnuts were nice but not spectacular, and the warm chocolate tart was delicious but a tad too sweet.
Dos Caminos on Park Ave S and 26th St. is my least favorite restaurant of the group. The food is consistently too salty, but the marguaritas are good, and the chocolate bread pudding dessert is a wonderful combination of textures and flavors. The Dos Caminos branch on Houston and West Bway actually has better food overall(not so salty) than the Park Ave branch, but the atmosphere is much more casual and the room is much smaller.
Of the 5 restaurants, Blue Hill and Tamrind are the 2 that we look forward to re-visiting.