I stayed at Mercure Mont Blanc for business. It is a nice apartment-style hotel as pointed before. Rooms are large and well equipped. My only complain was about the strange and weird sweety smell from room. It didn't actually bother me, anyway.
Location is not that 5 star place, but far away from being rough. It's located in a good neighbourhood. A shopping mall is next door (about 5 minutes in an easy walking), but beaches are a bit away and going to the Old Town by taxi is mandatory. By the way, it is really advisable to call the front desk for a cab some minutes in advance.
The restaurant over there offers a nice menu. Breakfast is simple for the kind of this hotel but it is yummie.
Front-desk and staff are all very kind and respectful.
As a final issue, free wi-fi internet connection is provided, but I had some problems with it, once it was very common to have the signal lost, mainly during the morning and some hours in the evening.
All in all, that's a good option for business. I supposes that this place can be affordable for leisure as well, although I would recommend some other place to stay closer to the Sao Luis main attractions.