Attached is the full case study from the eIFL-FOSS ILS project's Malawi project. It's about Koha, but I think their learning points are useful for anyone moving to an OSLS:

• A pilot library can serve as the leading edge in a potentially substantive consortium-wide migration to a FOSS ILS. 
• It is advisable to give yourself enough lead-time for the evaluation of a new ILS. 
• In order to learn new skills, libraries will often need to reach out to non-staff for initial assistance; the FOSS community is familiar with sharing skills and knowledge and can be appealed to for help. 
• Complex systems often take many attempts initially in order to achieve a successful installation; do not be discouraged if your installation fails once or twice or even ten times; this is how systems librarians master new systems. 
• Integrating a FOSS ILS into other programmes and projects within an institution can significant increase the base of knowledge and experience with the software available to the library in the future. 
• Sometimes the most efficient route to a new catalogue is to start afresh. 
• Take advantage of fundamental technical training opportunities whenever they arise.