Despite being mugged on my first night there, I thought Douala was a great place! There was always lots to do. Life is as expensive or cheap as you want to make it. There were some great, expensive restaurants with some of the best steak I've ever eaten, but also some great bargains, like La Marsellaise down the road from the Akwa Palace where you could have a good 3 course lunch with wine for very little. Even many of the expensive restaurants were very reasonable if you had the fixed-price menu at lunchtime. Supermarkets were pretty reasonable and the Castell beer very drinkable. If you go to a club with a few friends, buy a bottle of spirits. This is expensive, but you get a lot of mixer drinks, fruit juice and ice included. They'll mark your bottle for you, so what ever you don't finish you can have next time you go back and you then get a new lot of mixers.
Weekends away in Limbe, Kribi or Bamenda can be very enjoyable. I think you can have a very good time there if you want too.