Abstract : In spite of the growing interest for grids and cloud infrastructures among scientific communities and the availability of such facilities at large--scale, achieving high performance in production environments remains challenging due to at least four factors: the low reliability of very large--scale distributed computing infrastructures, the performance overhead induced by shared facilities, the difficulty to obtain fair balance of all user jobs in such an heterogeneous environment, and the complexity of large--scale distributed applications deployment. All together, these difficulties make infrastructure exploitation complex, and often limited to experts. This paper introduces a pragmatic solution to tackle these four issues based on a service-oriented methodology, the reuse of existing middleware services, and the joint exploitation of local and distributed computing resources. Emphasis is put on the integrated environment ease of use. Results on an actual neuroscience application show the impact of the environment setup in terms of reliability and performance. Recommendations and best practices are derived from this experiment.