I don't have the Horseman Zoom Finder, but I've used the current model Linhof Multifocus Finder, which is the same idea. The distance setting corrects for parallax by tilting the finder on its base.
If the Horseman finder is even remotely like the Linhof, it will provide a much brighter and clearer view than the VH-R finder. The VH-R finder is cluttered with framelines, and I find it very hard to see clearly without the eyecup, which is almost always missing on used VH-R's and is no longer available as a replacement part in either the US or Japan (yes, I tried).
The VH doesn't have a distance scale. It does accept the same infinity stops as the VH-R and earlier Horseman press cameras and often comes with one or more pairs installed, so if you're handy you could set a pair of infinity stops for a lens of your choice, and then with careful measurements create your own focus scale that you can tape to the bed.
The rotating back accessory is pretty unwieldy IMO - more of a studio than a field tool. For clarity, the camera's own back rotates - you don't have to remove it to change from horizontal to vertical. As Keith pointed out, the accessory back allows you to keep both GG and rollholder on the camera at the same time. It's a lot bigger than the camera's own back, though, and hangs way over the edge of the camera body.