Milu, the three middleware user interface

Many Grid infrastructures are nowadays serving the scientific communities. Those infrastructures are routinely accessed through some client software generally called: User Interface (UI). Installing and configuring such Grid clients is a challenging task for non expert scientific users even today. Miramare Interoperable Lite User Interface (MILU), is a software which targets mostly this kind of users by providing them a Plug&Play command line interface which contains multiple clients for accessing the gLite, ARC and GT4 middlewares. The package has been developed and evolved significantly during time. Through this evolution process we have always considered the incoming users' requests as natural requisites for the future development. This strategy provides the evident benefit of having a software which better accomplish its purpose, which, in MILU, is to allow a concurrent usage of different Grid infrastructures and create the foundation for more complex scientific gateways. This paper provides a complete overview of MILU and reports on its usage experiences gathered in the EU-IndiaGrid and e-NMR communities, and as a production UI in our local Grid environment