The quality of realistic complex wireless sensor networks requires several non-functional aspects to be accounted for starting from the early phases of the application development. The most relevant aspects that need to be considered for optimization trade-offs are for sure computational efficiency (in a wide sense) and network lifetime. At lower level these aspects are measured as power/energy consumption and execution time. These are though not the only non-functional aspects to be considered: code size, memory requirement, security, reliability and other properties play often an important role. Accounting for and managing all these aspects explicitly and in an ad-hoc manner for each and every application deployed on a WSN is a time consuming and complex task. This paper proposes a portable, flexible and extendable framework for the description and management of non-functional aspects in the wireless sensor network context.