Cleanliness had a different meaning over there. Everyone's house and place of business was very clean. Spotless. However, they would simply sweep up everything and put it out on the street. As long as it was not in there house, it was fine. Bizarre. Food wrappers everywhere. Empty bags of 100ml alcohol (Konyagi, etc) everywhere. I traveled by public means and the view of the roads did not leave of good impression. Do not get me wrong, I still had an amazing time. Even gorgeous Zanzibar had piles of garbage if you did not stay at a resort.
I spent very little time in Dar. It basically was the gateway to Zanzibar. Because of its reputation for crime and not wanting to be in cities but in nature, we only spent two nights there. As a music lover, I really wanted to visit places such as the ones described here: http://www.nytimes.com/2014/02/23/travel/where-tanzania-taps... I was there at the wrong time (Sunday nights) and the venues were far from my hotel. Would have loved to go if I knew someone.
I had better safaris elsewhere, but Ngorongoro itself is magical.