I think that was the same conclusion I came too. Both produced very good images, but the auto iris in the HS60 worked better than the Z4 so gave the image far better blacks which were always very good - much like a DLP. The Z4 often looked grey during normal scenes, but could do a good black level in a predominantly dark scene. The HS60 was almost twice the price of the Z4 so there was a bit of a price diffence. It seemed to me almost that it boiled down to how well the auto iris was implemented, and I think Sony are ahead of everybody else on this right now IMHO.
Gary