Other considerations
Speed is a hard thing to grasp. I mean, often times the "filling of a pipe" is done so using aggregate users of the SAN. So... perhaps a better way of looking at things is how many SANs using a singular client, can saturate the line. It should be fairly easy to saturate a line when considering requests over a multitude of clients.
It's possible that a SAN CAN saturate 16Gbit, for example, if using ONE client... but how many drives and what config was able to pull that off? Again, it sort of matters when considering how a particular SAN storage unit scales.
So things to consider:
1. Number of clients
2. Number of pathways
3. Number of drives
4. RAID level
And probably a lot more....