E-Government (e-Gov) is becoming an important means to produce value for citizens by using innovative technologies in the delivery of more advanced, efficient and personalized services. In this paper, we propose a model for the assessment of the service value defined as the trade-off between benefits and sacrifices perceived by citizens according to their service usage experience. Since human perceptions are subjective and uncertain in nature, the model proposes the use of fuzzy concepts to effectively represent and handle data under uncertain conditions. The suitability of the proposed model is shown by its application on a case study in the e-Gov domain.