living / working here in dar Es Salaam has it's challenges (traffic being the main one) but i've been to a lot worse places. People are friendly, it's safe enough if you live in the right places (Msasani Peninsular is good) and there are plenty of restaurants, bars, etc. Malaria is an issue here but just take the correct precautions and it's fine. Plenty of modern doctors/hospitals/dentists if required. I can have a blood test here, and have the full results in 20 minutes, in the UK it takes up to 2 weeks!! Makes you wonder where the UK is going wrong sometimes.
Regular power cuts, and obviously the tropical diseases/beasties are all what you would and could normally expect living in Africa. It's not a bad place at all.
Any specific questions don't hesitate to PM me and ask.