I booked the Fairview based on reviews here on Tripadvisor, and I wasn't disappointed. A lush, safe, friendly oasis in the middle of Nairobi.
Booking can be a minor hassle as they don't seem to be linked up to any of the international online booking systems, however a quick phone call told me there were rooms available on the date I wanted and an e-mail confirmed my reservation. The hotel is just northwest of downtown Nairobi but is a quick and cheap taxi ride away from both there and Upper Hill, Westlands, etc.
Reception was friendly and welcoming after a long flight, and the room was pleasantly decorated and clean. The bathroom fittings and tiling were perhaps a little aged, and I was slightly concerned to be on the ground floor given that the windows appeared to open, but security on the site appears to be good. Wireless internet access was available in the room and surprisingly speedy.
I had dinner in the poolside restaurant which was pleasant, and breakfast in the morning was a western-style buffet. The hotel has private gardens and pathways running between the various hotel blocks, this provides a peaceful oasis away from the crazy chaos that is Nairobi.
Compared to what you can pay to stay at the Hilton or the Intercontinental (an outrageous amount for not very much), the Fairview is excellent value for money for the service, location and setting of the hotel, and is my first choice of hotel when visiting Nairobi.