In previous work we have presented the ZENTURIO experiment management system for performance and parameter studies of parallel and distributed applications on cluster and Grid architectures. In this paper we describe experiences of an on-going work, targeting the implementation of ZENTURIO on top of the Open Grid Services Architecture (OGSA). We analyse the opportunities offered by a Web services toolkit to develop Grid services as required by OGSA and compare them with the solutions offered by the Open Grid Services Infrastructure (OGSI) specification. Issues regarding proxy management, service lifecycle, UDDI service repository, firewall management, Factory and Registry services, service throughput, and security are comparatively analysed in both implementations.