Review (5/5): Good size
I bought this to shave in the shower both at home and in the gym, and it works well for both. There is no such thing as "truly fog-free," as fog is the condensation of the humid air/water in the shower on the colder mirror surface. However, it's easy to defog in a second -- put a little soap on it and wash it off, and the mirror stays fog-free for 5-10 minutes, which is perfect for my shave. (If you have a window open in the bathroom, it's entirely possible the air will be dry enough that you won't even have to do this.)
The mirror is large and enables easy viewing of my face to shower with. The hook works well; for the gym, I pair it with a bag that has a suction cup, which I can hook it off of. At home, I use it with a suction cup hook, and hang the razor on the bottom, just as the image describes. Overall, the setup works very well, and I've become addicted to in-shower shaving.