I was there a month ago. Expensive,traffic is a nightmare,gotta be careful of what you eat,and it's not safe to go out after dark (as told to me by a local).
People are friendly enough,but infrastructure is shot,the airport is on the far side of Luanda and there is little to no public transport other than taxis that charge an arm and a leg. Everything is done in USD, local currency is kwanza and it's 100-1 against the dollar. A steak will cost you $35.A 1.5L bottle of water will cost you $5.
Rather go to Namibia.
Oh,and getting a visa is a frigging NIGHTMARE,and frigging expensive as well.