I have dove with one. At the time I was more concerned with scootering, which I thought the mask might be good for.
Visibility downwards is terrible, I could not look down and easily confirm gas on a deco bottle without making a big production of lifting it.
Sideways vision to the left ain't bad because of the window. To the right, the computer is there, so that's obstructed too. This is a high volume mask, although not as high as the 1980's 3-window US Divers monstrosity.
I remember thinking this would be a PITA to install reader lenses into. There's no place for them.
The apparent distance for the computer display is great (it wasn't a huge focus shift to bring my gaze from infinity into the mask), and provided there's adequate light, the digits are crisp and legible. I did not dive it in the dark. The computer is pretty standard Oceanic/Aeris, so if you're used to those displays it is plenty intuitive.
It is easy to update your status regarding depth and time, but for me (and others, in conversation later) I felt that it wasn't as if I had this data superimposed on the world - I had attention either outside or inside.
I didn't have a camera along, but my impression was that if I had my face to the back of a housing, it would be a big focus jump from viewfinder to depth, bigger than infinity (outside) to depth.
Coming from an Atomic Frameless, I felt that I was moving my head around a lot just to keep track of my surroundings. Because the mask was so restrictive to vision on the right side, I felt it was not a good tool for scootering.
I didn't really consider the price/value ratio, but given the results for me, and the price, I'd rather get a couple of Atomic masks and a X1 computer.
Hope this helps!
All the best, James