Put the SAN vendor to task. The vendor (SAN Engineer) should be able to whiteboard three or four specific solutions that the company has implemented and provide a discussion of the pitfalls and dependencies of the solutions. Specifically, ask about interchangeability of components and driver functionality as related to your end-storage devices and your applications.
What specific value does the functionality of the solution bring?
Better performance or flexibility?
Does it require a costly upgrade of software?
The vendor should know the best hba that works with a particular operating system and specific interoperability issues with the major switch manufacturers. Make sure you understand port cost and large- versus small-switch costs. This mainly pertains to a large fabric. If they cannot address these or your specific questions regarding functionality, look somewhere else.