He's obviously not a storage guy....missing the point completely...
The continuous debate of NAS vs SAN based Arrays. First of all notice the difference..SAN is indeed only a network..and i couldn't care less if it is Fibre Channel, FCOe (or better CEE), iSCSI, or whatever protocol comes along in the future to talk accross that network.
The discussion should be : file server (=NAS) vs external disk array (= what you connect to a SAN).. And again the thing is : a file server is primarily used to connect PCs or Macs.. to provide file shares and nothing else.
An external array is designed to connect to servers, not PCs (and a role of one of those servers could be..file serving).. It is mostly used for applications like Exchange, SQL, Oracle to name a few. Those are not built to use file shares to host their databases. They expect a 'dedicated' disk (in case of an external array,a volume presented to them).
And as someone else also mentioned yes, there are NAS devices out there that can also act as an external disk array (eg. using openfiler or FreeNAS). What they fail to mention is that using a standard file server will introduce single points of failure... now, i don't want to bet my business on a device without redundant controller capabilities...
And yes, there are also NAS solutions out there that do tackle the 'SPOF' issue..but then you already see where we're going...its actually two NAS boxes connected to...an external disk array..voila..full circle..
There should be no debate NAS /SAN ...both have their use.