The Zone VI camera's specs changed over time as different manufacturers made different designs. The Ultralight model was made by Calumet after they purchased Zone VI. I have an older Zone VI camera and a friend has the newer Calumet version. His camera weighs 4 lbs, has 22" of bellows and a bail back. Both his and my camera will focus a 90mm lens somewhat closer than infinity on a flat lens board with the standard bellows but in both cases movements, while adequate for landscape use, are rather restricted by the bellows. Both cameras can exchange the standard bellows for a bag bellows. My Zone VI uses a 4" square lensboard and while I don't know for sure, I believe that his does as well. I bought my camera used and it came with one of the aftermarket "bright screen" focusing screens, and my friend's is also very bright and may be an aftermarket screen as well, I don't know. I haven't measured movements but they are more than adequate for the landscape photography that the two of us do more often.
I'm quite happy with my older Zone VI and my friend must be happy with his since he's had it for at least ten years that I know of. His is lighter than mine but I see no reason to spend money over 2.5 lbs. I know folks with Chamonix and Shen Hao cameras and they're fine cameras, no doubt about it, but ultimately no better than a Tachihara or Zone VI camera, and a used Zone VI will be less expensive.