In order to create a successful software product and assure its quality, it is not enough to fulfill the functional requirements, it is also crucial to find the right balance among competing quality requirements (QR). An extended, previosluy piloted, interview study was performed to identify specific challenges associated with the selection, trade-off, and management of QR in industrial practice. Data was collected through semi-structured interviews with eleven product managers and eleven project leaders from eleven software companies. The contribution of this study is fourfold: First, it compares how QR are handled in two cases, companies working in business-to-business markets, and companies that are working in business-to-consumer markets. These two are also compared in terms of impact on the handling of QRs. Second, it compares the perceptions and priorities of QR by product and project management respectively. Third, it includes an examination of the interdependencies among quality requirements perceived as most important by the practitioners. Fourth, it characterizes the selection and management of QR in down-stream development activities.