We had a wonderful stay at Riad Elixir: It was our home from home for 5 days and our base for exploring Marrakech and beyond.
Don't expect modern luxury: some of the charm is in the old fixtures and fittings...but everything works!
Our host Moha was excellent, arranging excursions for us within Marrakesh and out to the Atlas mountains.
Be warned that, while we could lock our bedroom door from the inside, we couldn't lock it when we left. However, the door of the Riad is always locked, Moha is usually around and there are only 5 rooms so you quickly get to know everyone staying; it felt really safe.
The Riad is within the Medina meaning that it is only accesible by foot. Taxies can drop you a couple of minutes walk away. We would recommend getting Moha to arrange a transfer for you, so you get taken to the door. It is about a 30-minute walk from the Riad to Djemaa el Fna depending on how lost you get wondering the Souks. We recommend using Google Maps for navigation or getting a taxi from the nearby Bab Taghzout, but be prepared to bargain hard!
If you want comfortable, authentic accommodation within the Medina with a great host, go for Riad Elixir.