First of all I like both of them but there are considerations especially near a wall or foundation just like any other plant.

An Evergreen Cotoneaster is a nice short showy shrub and the birds love 'em! They are slow growers but remember that these are shrubs and the roots may end up screwing-up your wall in ten years so that it doesn't "retain" anymore.

The Winter Jasmine smells great but it can get up to 15' high! Another thing to think about with the wall is that the rootstock can get very large and the vines may attach themselves to the mortar and eat it away. It may also climb your trees and choke them out.