When I purchased my NN3 MKII I commented on this forum that it was a superbly engineered device, but Nick has managed to find room for improvement with the introduction of the Nodal Ninja Anti-Twisting Camera Mounting Plate.
Thanks Nick, mine arrived yesterday and has made using the NN3 MKII even easier!
I did find it tricky lining up the camera so that the lens axis (principal ray) was absolutely parallel to the top rail, but this device makes it simple.
Looking through the topics on the forum there is a lot of discussion about the settings on the top and bottom rails, but even if these settings are absolutely spot on, if the lens axis is not parallel to the top rail there can be parallax introduced, especially if the camera/lens is tilted vertically, but with the CP-2 Camera Mounting Plate this is no longer a concern.
I started out by building my own panohead but when I changed cameras it no longer had the right settings for the new camera so I purchase a friction type panohead, which I soon replaced with an NN3 MKII, which was a huge improvement and is now even better!