A nice place in East Africa. Despite security issues, always be on guards in busy and commercial areas.
Avoid places where there are no international travelers. Also, lock valuables in your hotel and do not move around with much baggage. The city traffic can get terrible and plan your trip well to avoid delays.
Kenya has many interesting places to offer you. Natures especially, is the best place to be. See the wildlife, that you might hard to see in other places.
Traffic crazy! specially if you are driving! traffic light system good if police allow it to work automatically as designed.
Taxi Minivans and midi buses driven by escapees from local mental institutions. Hustlers in the streets around to city center make it an unpleasant experience to walk about, on several occasions we were forced to return to the hotel to avoid further hassle. Although more advanced than Kampala, Uganda it is not as pleasant by comparison.
In general the people are friendly, however it has the nickname Nairobbery and this has come about because of the criminal element, it's very unsafe outside of the well guarded hotels.
I was the victim of two corrupt policemen who accused me of driving on the wrong side of the rod so they could extort cash from me. It left an unpleasant taste as I'm used to the police being friendly and helpful and understand that tourists bring much needed cash to the country. The airport arrivals hall burned down in early August and this has impacted on the efficiency and comfort of the passengers. There are some good quality hotels - I stayed a few hours in the Boma which is of a high standard, very clean with attentive staff. The road traffic and pollution is appalling, it takes forever to get through the city traffic. The heavy trucks, buses spew out clouds of horrible diesel fumes which would not be permitted in more environmentally aware countries.
It is a pity that Nairobi has a bad reputation due to its criminal statistics. But if you follow some basic rules, you will not have any problem with that.
I never felt insecure, even when I was out in the night (of course with car/taxi).
Nairobi itself doesn't have any attractions, unless you like traffic jam! :-) You have to go out of the city to see some wildlife.
Nairobi has the usual entertainment and night life spots but do not expect European or American standard! However, most of the food and drinks are cheaper than Europe or America.
This was my first visit beyond the airport, so my observations are a bit limited. Nairobi is is a major African city with a good road network and an effective airport.
I have no direct experience with the city's bus network but saw large numbers of fairly modern buses traversing the city at a good frequency. My experiences with taxi drivers have all been positive. I used the desk at the hotel arranged the return trip. The many modern buildings and a wide range of industrial and commercial activities reflect an urban affluence that is the envy of many elsewhere in the continent. There are numerous hotels ranging from the very cheap and maybe cheerful to elegant and sophisticated 5 star variety. The city has a number of parks - some with wild animals - all worth a visit even if you only have a few hours. Tour agencies abound but stick with the accredited ones. Nairobi is the traditional launching place for tours to game parks and Victoria Falls but it has museums and other places of cultural interest worth exploring. I would ask the hotel staff for advice if I have not previously researched my activities.