Beni Mellal is not a tourist place, and few travellers come by. But the city serves as a good base for travelling in both the Middle Atlas and the High Atlas mountains, as well as to the Cascades d'Ouzoud.
The market here is good and genuine, and few stalls will have silly tourist products. Most shop keepers would also be charging you prices not too far above what Moroccans pay.
Beni Mellal is quite a big city, and one of the fastest growing in Morocco. It serves as the capital of a large region right in between the High and the Middle Atlas mountain ranges.
The local authorities have responded to the immigration from the countryside, by constructing a couple of attractive, if brand new, structures in the centre of town. If anything should be worth discovering here, this might be the place.

Practicalities

Beni Mellal hotels
Al-Bassatine (t. 023 486805) Marhaba (t. 023 483991) es-Saada (t. 023 482991) Ain Asserdoun (t. 023 483493) Kamal (t. 023 486941) de Paris (t. 023 482245) Tassamet (t. 023 421313) Venisia (t. 023 482348) Zidania (t. 023 481898) Chems (t. 023 483460) Ouzoud (t. 023 483752)

Beni Mellal has pleny of hotels, providing both for those on a tight budget, as well as those asking for comfort. Prices are OK.
Most travellers eat in their hotels. Among hotel restaurants, the Ouzoud and de Paris are recommended. Among regular restaurants, the Tawada is very good. Several smaller joints fix sandwiches, which often can be nothing short of excellent quality.
Being a large place, Beni Mellal has all you would expect. Plenty of banks, a few internet cafes. A tourist office will be helpful in arranging trips into the Atlas Mountains.
Should you rely upon public transportation, Beni Mellal is slightly on the awkward side, since stations are out of town. Connecting between stations set apart, take a taxi, otherwise you're in for quite a walk. there are good connections for going south and north.