Never had any problems in NBO, spent several weeks there over the years, generally 2 weeks at a time in Kenya, at least 1 in NBO. we stay with family so can not comment on hotels.

As for the traffic, if you try and travel from the airport in to town in the morning rush hour it could take you well over 3 hrs, I think the worst I heard was my Wifes sister spending 4 1/2hrs in traffic. Sadly the main road from Tanzania through to Uganda and beyond runs straight past the airport and in to town.

Some nice restaurants to be had, service can be suspect at times. We tend to stay in around Westlands area rather than downtown when in NBO.

Lounge at NBO (at least for CW passengers) is a real trek from the gates hidden away on the 4th/5th floor somewhere, quite small and generally poorly stocked from my experience.