Yes, we have heard this before from companies, but never from a company that is not trying to raise money from investors. Hitachi is a very conservative company, and for them to announce this means, in my opinion, that they are very close to having a working production product.
During his talk, Hitachi's Ken Wood said that a 2 TB holographic drive will be able to read at 2 Gb/sec or 238 MiB/sec. Ken also discussed a 12 TB media option that would support 6 Gb/sec read or 715 MiB/sec read speed. Write speeds are far lower than read speeds as data is validated end-to-end before it is committed. The host side will validate that data transferred to the drive matches what was in the buffer before it was committed to the drive. This seems like a huge advantage over current methods and ensures end-to-end preservation of data.
Next came Akinobu Watanabe, who discussed the error rate, which has significantly improved over current optical technology to 10E21 bits, adding ECC to each block. This is far higher than current optical technology.
If the information provided is accurate, then I would consider this the first disruptive technology to hit the storage industry in a very long time. Needless to say, I am very impressed and am hopeful this technology does make it.
By the way, you can see the conference presentations at the IEEE site.