A great place to be. My favourite in Africa. The people are really nice.
Douala is like any other large African city. Hot, humid and a bit crowded. However, although the roads are deteriorating in the present rainy season, driving is not really a problem and although there are always police road blocks late at night the harassment is not too bad. Just talk to them in English, even if you're completely fluid in French.
There are quite a few good hotels. The Meridien, Akwa Palace and Ibis are all acceptable. I live in the Akwa and it's fine with a good, clean swimming pool.
The range of restaurants is excellent and although prices are high, expect excellent food with a very high standard of meat and fish. There are also good Greek, Chinese, Lebanese, Italian and Japanese restaurants.
Night life can be lively and there are many good bars, pubs, cabarets and discotheques, some with very good live music. As with most cities in Africa, make sure that if you go out after dark you don't go on foot unless yoiu have a particular fetish for getting mugged!!
If you want to know more specifics PM me. I'm in Douala at the moment.