I've travelled to Nairobi quite a bit and tried all the mainstream hotels and for the first time stayed in a really memorable hotel.
I'll definitely go back to the Stanley due to the combination of the great service (a standout was waitron Everestus in the Thorn Tree eatery on the ground floor) and being in the thick of Nairobi's city life.
Food in general was great - the breakfast buffet was impressive.
The rooms are comfortable - everything works exactly as you'd expect it to.
The company I work for, along with a Kenyan bank, held a joint breakfast press conference on the hotel premises and it worked out really well, accommodating press/media personnel as well as the various stakeholders/dignitaries.
From the Stanley I was able to walk to meetings in the city and on the one occasion I needed to drive, the Stanley provided the most friendly, efficient driver (Eric).
The hotel is about 20 mins drive to/from the international airport during off-peak traffic.
Everything about the Stanley was easy and enjoyable.
The facilities meet one's needs.
Special mention must be made of the 1st floor bar/lounge area which is really peaceful, calm and comfortable - a great environment for discrete meetings.
I honestly can't think of a better Nairobi business hotel. The Stanley also seems to be well embraced by tourists judging from the organised tour groups I observed checking in/out and gathering for meals...