I took my Mum and a friend to Marrakesh for a week' holiday in May, and Dar Tasnime was ideal in many ways.
It is close to many of the cultural attractions, and within walking distance of many more (even with some very slow walkers in-tow!!!).
Although there is re-development going on around the riad, (which was a bit noisy and dusty during the day), once inside all is tranquil and beautifully arranged. I looked in all the rooms and can confirm that they all live up to the web-site photos - they're beautiful, and each has its own individual character. I was lucky and had a balcony looking over the courtyard, but my Mum was equally pleased with her pretty and cosy room on the ground floor.
Although there is a pretty lounge adjoining the courtyard, the main public area is the terrace, where we ate generous breakfasts (included in the price), lounged in the sun, and enjoyed evening G+T's (duty-free's!) and an assortment of snacks from the nearby 'Nut vendor' and 'local store'! Chakib the owner was more than happy for us to help ourselves from the kitchen, (and we tried to tidy up after ourselves!).
I would say that the biggest gem of all at Dar Tasnime is indeed Chakib! He is the most warm and helpful hotel proprietor I have ever met, he speaks perfect English, (having spent 10 years in the US), and being a Marrakechi born-and-bred, he will give you all the info and tips you could possible wish for. He made us feel exceptionally welcome and safe in a city which can sometimes be challenging! He will give you restaurant recommendations (the new place nearby is beautiful, with great food and service plus very high quality musicians and an unobtrusive but beautiful Belly dancer(!!), and can arrange most anything you have in mind.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.