I fully endorse what others have said about Dar Silsila. I visited with my wife and another couple on the strength of these reviews and wasn't disappointed. I recommend that you take up Jean-Patrick's offer of a pick up from the airport. We were met straight out of immigration and taken to the Riad. Given Dar Silsila's interesting location through a tunnel in a narrow alley you may have trouble finding it on your own.
We booked a meal at Dar Silsila the first night and as described by the other reviewers it is highly recommended. Beer and wine (Moroccan) are available. The dining room is also a good place to get to know the other guests and make friends.
Take full advantage of Jean-Patrick's local knowledge of the city and its restaurants. He recommended where to eat for the best experiences and booked an excellent restaurant for our meal on the last night.
Dar Silsila is located within easy walking distance of the Souks and the Djemaa el Fna square. We spent wonderful hours 'lost' in the souks, bartering for local crafts - hand woven fabrics, beautiful joinery, metal objects etc. The local people are incredibly helpful and friendly and when they offer to help they really mean it. We did not feel threatened or pressured at any time. Dar Silsila was an oasis of peace at the end of the day. It was amazing how we could find our way back through the maze of streets and alleyways.
Dar Silsila is highly recommended for anyone wanting to explore this fascinating city.