That's really a tough question because BlueArc is so new. Based on limited knowledge of their product, it seems that they could indeed do a great deal of speed-up in the file serving aspects for a NAS product. It does take a product (especially a storage product) to stabilize in the field so caution is always advised when introducing new technology. How long it takes and how easy it is to introduce fixes is a big factor in determining whether a product will be adopted quickly by customers. Right now, there's not enough real information to form any conclusions. As far as performance goes, check the Web site http://www.specbench.org/osg/sfs97/results/indexall.html for products that have been tested against a known test standard.
One other note on NAS performance, the performance can be throttled by the processor overhead in handling the IP protocol stack (and things like segmentation and reassembly, integrity checking, etc.), the busy-ness of the Network (read congestion), and the other aspects such as security, network connection, NIC card, etc. So, depending on the individual situation, the fastest NAS product may not help when there are other limiting factors.
This was first published in April 2001