Cotonou isn't so bad. It's much much safer than Nigeria for one and there's a lot to do and it being right by the ocean is a plus. It's just a matter of being smart and avoiding going to certain areas you know wouldn't be safe. Power is pretty much constant but cuts from time to time for a few minutes or a few hours but many places have generators and it really isn't much of an inconvenience. Internet is as you would expect in a third world country, connection is not great and very expensive, just don't expect the type of speed you would get in North America.
There are more than a few supermarkets including a huge Western style supermarket. Prices of stuff like cereal is expensive but u can get a great selection of fruits and vegetables at the markets. There are also many different restaurants and bars, including sushi, and the beach is s popular getaway on the weekend. The US community here is pretty large, a lot of peace corps volunteers and embassy staff so am sure finding friends will be easy... Let me know if you have any more questions, would be happy to help and good luck!
