What Makes A Good SAN?

Photon Ghoul asks: "I'm currently researching storage options for my company. We will be choosing a NAS (Network Attached Storage) or SAN (Storage Area Network) solution and are looking at different vendors, including Sun and Network Appliance (but NOT EMC). It must be used in a heterogeneous environment (NT, Sun and Linux), have HA, and easily scaled. I was wondering if readers of Slashdot have had any experience with NAS or SAN vendors. Who should I look at and who should I stay away from? What criteria should I be looking at?" We've talked about SAN Solutions before and there was also a question on the comparisons between SAN and NAS which wasn't well responded to, but had some good information nonetheless. Has the the SAN/NAS landscape changed much since these were asked?