As my son pointed out, within a week we had eaten replicated meat and went to a hologram concert, so we are getting closer to living in a Star Trek universe. Part of our rational for going at all was that if we were on the Enterprise and heard there was going to be this concert in the Holodeck, we'd have been there. We also knew that at the very least the music would be great...and it was.
If you walked into the concert not knowing it was a hologram, you would have thought you were seeing a Buddy Holly/Roy Orbison impersonator. They looked 3 dimensional, light seemed to reflect off them, they could turn around and gesture to the band, though i have no idea what the band could see or how it was projected.
I was hoping it would be a holographic representation of actual performances they once did, but they seemed more like images built from elements. It was fascinating and enjoyable and showed clearly that there is a future for this tech.
I do wish they could add some speaking, even if its just saying something about the song they were about to sing. A little audience patter would make it a bit more realistic and easier to relate to.