As there’s no international classification of hotels, star-rating system is not applicable to Morocco. I would advise you to pay attention at traditional types of accommodation: riads, kasbahs, ksars etc. Of course you may choose any worldwide hotel chains but they won’t bring you so close to Moroccan culture.
Two main common traits of traditional guesthouses are Moroccan-style decoration and inner yard, that helps women to hide from the eyes of strangers. Actually it depends on the owner, how he will name his type of accommodation. The same type of building may have a different name.
2 or more storied house of a wealthy merchant. Usually riad is located in historical centre of a city. The inner yard (atrium) often has a roof. There’s definitely a fountain in the middle, a small garden (or some trees in pots) and mosaic tiles. Depending on cost riad may be modestly or richly decorated.
It’s hard to find a difference between these 2 kinds. Both refer to a settlement that is surrounded with a fortified wall. Buildings inside of it border on each other.
As a guesthouse a kasbah is a small square castle made of rammed earth. There are towers on every corner. Ksar is a fortress made of adobes with several buildings on its territory. Ksars are usually located in rural area, while kasbahs – outside a city (town). If one surrounds several kasbahs with a fortified wall, they become a ksar.
In Merzouga you will see one- and two-storied private houses that are build in shapes of circle, infinity etc. that surround inner yards. All the streets look the same. The difference hides inside.
For example, «Chez Youssef» hotel – one-storied building erected with the use of traditional technologies and materials – clay, straw, wooden beams and ceilings covered with cane. There are 2 inner yards. Guests can ascend the roof to take a look at Erg Chebbi and the bigger yard with a palm tree. Despite of it the hotel is modern – new beds, air-conditioners and wi-fi.
Some of guesthouses can offer you some cultural experience too. For example this private hotel in Agadir gives you a possibility to admire stone-carved ceiling in the lounge. Not every historical building has such a ceiling.