I stayed at the Tribe for an extended period of time (over 40 days), so I truly feel as though I know every nook and cranny of the place.
The good: This is a lovely hotel if you are passing through Nairobi for a short period of time. First off, the staff is wonderful. They truly get to know you and are very, very accommodating. I was sick at this hotel, and the staff checked up on me constantly. The hotel is also very convenient to several Embassies, NGOs, and the U.N. Village Market--a mall within two steps of (very safe) walking distance has literally everything you could need. Tons of restaurants, a grocery store, and the Masai Market on Fridays. However, the hotel is not centrally located in Nairobi--it is far away from many of the touristy sites in Karen or the Central Business District, for example--although you will be in a beautiful, upscale, leafy suburb.
The bad: For business travelers, this hotel has a lot to improve upon. Wifi is spotty at best. Lighting in the rooms is so dim it makes it difficult to work, and an awkardly shaped desk (oval-shaped with "basins" of sort) makes it harder to get anything done comfortably. The lobby constantly blasts loud house music--and even when everyone in the lobby is on their laptops and working (and someone requests the music be turned down). The restaurant is extremely inconsistent: the same dish can be delicious one day, terrible the next--and can also take (literally) 1.5 hours to arrive one day, or 15 minutes the next.
The hotel needs some upgrades, particularly to their air conditioning system (I had two rooms with faulty air conditioning)--they are currently doing construction to the lobby and ostensibly are working to fix the wifi.
Overall, I am giving this hotel a good score due to its staff as well as convenient location. But business travelers who don't need to stay in this neighborhood might be better suited elsewhere.