If you enjoy your cow (and I mean every single bit), try Babacoa in Omotesando. It's a nicely lit, fairly spacious Brazillian buffet located underground. This place offers two courses for either lunch or dinner (don't know why they have menus....). During lunch they have a salad bar set or the full meat course. Dinner is the same as the full lunch time meat course but offering an all-you-can drink menu as well.
The salad bar is fairly impressive, with several premade salads as well as components to invent your own salad. Some items like fries, beans, and fried bananas are on the side. Lunch has a bit more. However, the primary event of the place is the guys who come around your table to serve you slabs of meat. Each table has a small paper mat describing the parts of the cow they're serving. But the items are all cooked quite well. They're chicken, sausage, liver, fried cheese and pineapple in addition to the various steaks they offer. The selection is limited but for a buffet the meats are prepared quite well. The night time drink menu isn't expansive but is unlimited. They offer various alcohols and will bring you upon request.
In general, this place is excellent for parties, friends and maybe a soon-to-be girlfriend if you can get her considerably inebriated ;)
Lunchtime price ranges from 1000-en for the salad set to ~2000-en for the meat set. Dinner is 4000-en for the non-alcohol course and 6000-en for the alcohol course.
Favorite Dish: The pepper steak and bbq pineapple are excellent. The pineapple goes down well after the enormous portions of meat you'll be served.
The people who created this restaurant brought with them a very festive Carnival spirit straight from Brazil. The festive atmosphere here turns every meal into a party and the excitement helps diners to continue to feed on simple but filling Brazilian buffet fare. The all-you-can-eat Viking dinner menu offer includes Churrasco sets at JPY3300. The accompanying side dishes found here are delicious and should not be passed up.
The sister reataurant of Barbacoa at Omote-sando. This restaurant offers the wonderful beef steak dish and also all you can eat dinner. The speciality is humberger steak!
Favorite Dish: The all you can eat program is very reasonable.If the night will be special, the humberger stakes or WAGYU(Japanese tederloin beef) steaks is the one I would like to recommend.