Like Phil Pascoe I remember one of these at school. Only our woodwork teacher, Mr Rand, could use it. None of us oiks were allowed near. IIRC it had a wooden lid (probably made by Rand) to keep dust and shavings off it. Late 60's, so it must have been there well before that. I remember Rand setting it up, and making himself a cup of tea while it did its job unattended. I think it probably had to cope with abused and chipped chisels on a regular basis. I seem to recall it has an oil sump and a pump that gives a slow feed of oil. Thinking about it there must be a filter down there somewhere to deal with wear metal.
I toyed with the idea of buying one, but ended up with the inevitable Tormek, and a Creusen bench grinder. I actually find the Tormek to be pretty quick. In most cases you are just re-establishing a primary bevel.
The benefit of the Viceroy is you don't get a concave grind - if the stone is flat, you get a flat grind.
Now there are opinions about that. One of my heroes of wood, James Krenov, ground his tools on a hand cranked grinder with quite a small diameter wheel, so the grind was radically concave. He could then hone it by just putting the blade flat on a fine grade stone. He wasn't entirely a hair shirt worker - he had an exceptionally good and accurate bandsaw, and a surface planer (but no thicknesser).
Rob Cosman uses an 8" grinder to establish a primary bevel - so again slightly concave. The Tormek wheel is 250mm (10 inches), so grinds slightly concave.