Yea they have definitely used at least 2 different types of display and one of them looks a lot better than the other IMO. Interestingly even the better looking of the two (can't remember the model now) is only a TN panel. Considering how much they charge for these you'd think they could stretch to an IPS! The early displays I have look lame in comparison, mainly becuase the blacks look dark grey at best. I had a brief look about a month ago and the newer panels they are using are available for about £40.
All of my displays have been updated to the latest firmware, the DOTXL mode is where its at imo and should of been available at launch. I used to like tiles but the square edges take away some of the detail in the animations as the corners were supposed to be round. 8-bit looks alright but you really need the thin black lines between the dots/squares for the art to look right. The human brain is clever and seems to automatically fill in the detail that would be in the black areas which it can't do if there aren't any! The HD upscaling modes are completely useless, theres simply not enough detail in a 128x32 source for it to work well and again the lack of black areas don't help with DMD animations.