Service-oriented systems engineering (SoSE) counts its two-decade history. Nowadays it is a way of developing and deploying applications as well as the whole enterprise systems. Service-oriented requirements engineering (SoRE) as an integral part of SoSE and as a new requirements engineering subdiscipline faces a number of different kinds of challenges. The early SoRE approaches were derived from the initial phases of traditional software development methodologies, and the later ones are original, taking into account the specific characteristics of service-oriented systems. This paper discusses the specifics of service-oriented systems, describes the paradigm related SoRE issues and provides an overview of the characteristics of service-oriented enterprise systems. All these specifics and issues entail different methodological approaches to SoRE. The special attention is given to requirements negotiation activity. The paper presents a view-based approach to derive the balanced service quality requirements from an initial set of stakeholders' needs.