In this paper we analyze several semantic-aware Grid middleware services used in e-Science applications. We describe them according to a common analysis framework, so as to find their commonalities and their distinguishing features. As a result of this analysis we categorize these services into three groups: information services, data access services and decision support services. We make comparisons and provide additional conclusions that are useful to understand better how these services have been developed and deployed, and how similar services would be developed in the future, mainly in the context of e-Science applications.