We stayed at this Riad for 5 days in February and could not have been more pleased with our experience there. Many others have noted the very excellent service of the owner, Jean, and his fabulous staff - I would second and third all of the positive comments!
I read a bit in a guide book somewhere saying that - staying at a Riad is like staying at a wealthy friend's home as a guest which feels like a calm oasis in the middle of a chaotic place (to paraphrase) - couldn't have described our experience better than that.
I would most definitely recommend arranging an airport transfer with Jean and his staff before your arrival. We never would have found the Riad on our own, as it is really tucked away in a series of unmarked alleys. It was worth the money and our sanity to have a driver waiting for us upon arrival at the airport, ready to take us to Riad Dar One.
The service at this Riad is above any other 5 star property we have stayed in when traveling. They go out of their way to assist you, and will aim to do whatever you ask of them. The people overall we encountered throughout this trip were super friendly.
Ask Jean and his staff for recommendations - they know everything about the city - from the restaurants to the price of items in the souks. I am thankful we asked so we knew what was fair for bargaining, etc.
Also, Jean arranged a day in the Atlas mountains for us with a local Berber man named Hassan. It was an INCREDIBLE day and worth every euro (or DHs) for the outing! We hiked between Berber villages and then had lunch with a local Berber Family in their home. There were NO tourists along this route which made it much more special and authentic. This guide, Hassan, only works with Riad Dar One and one other Riad in the Medina so if you have a day to take an outing, I would recommend it instantly.
Also, per other reviews we read, we arranged a trip to Les Bains des Marrakech - we spent a full afternoon here - HIGHLY recommend it! http://www.lesbainsdemarrakech.com/ - we did the Hamman duo - seemed very reasonable compared to spa prices in Europe and in the US and the place was really nice and relaxing. It was a bit challenging to find this location but luckily we found it in the end. The Riad staff drew us a brief map for our route to get to the spa which was quite helpful.
If you are headed to Morocco, make sure to stay a night or two (or more!) at Riad Dar One, it will be a highlight!