I like Adidas plimsols as I find them very comfortable, in saying that though I don't really harbour any serious brand loyalty towards them.
I can't think of any other branded sportswear I wear as it happens, other than football shirts and in this instance I buy the shirt for the club or country rather than because it's made by a particular manufacturer. I only own one shirt from each of Nike and Adidas (and don't have a preference in terms of quality or what have you), but own far more by the likes of Umbro and Diadora, for example.