Here’s the introduction :
As of July 2009, the perfect head mounted display (HMD) – the one providing exceptional immersion, superb image quality, a wireless and featherweight design for a ridiculously low price – does not exist. However, many users might find that a ‘good enough’ HMD can be found for their particular application. This document discusses the key attributes for HMDs, explains why they might be important, and offers some selection guidelines.
Thanks to them for writing and sharing this document !