Upworthy recently published an interesting video on the design that goes into a shopping mall which includes designing the right music and the difference between the music in the mall and within the stores themselves.
The key point with music was that the quality and mood of music in the stores needs to contrast with the less than attractive style in the mall. So not unpleasant but just more a mix in with the clatter of chatting and people walking which means the stores themselves, with carpet and fittings that enable warmer acoustics are more inviting and a sanctuary from the mall.
Downtempo, chill out and lounge can work best for stores who want that warm, relaxing and welcoming ambience. Retailers targeting the younger age groups can attract with louder music with energy and faster tempos.