It's essentially the 7G, without the audio ports, usb1 hub, and wrist rest.
The layout is a UK layout, with a few exceptions:
"Enter" is a larger American type. This steals the position from the # key.
"Backspace" is halved to be the size a normal key.
"`" is moved to be between "=" and "Backspace".
"#" is moved to be before "1".
As you're no doubt using a UK layout in you OS, the incorrect positions of "`" and "#" will go ignored, you should just pop those keys off and swap them back to be the correct layout.
Annoyingly, the shift of the "#" causes me to often hit "Enter" when going to hit "'" by mistake. :/
The switches are Cherry MX Blacks btw, not browns.
The reason the PS2 connection is prefered, is because the keyboard has an N-Key Rollover, allowing all keys to be pressed and registered at the same time.
The USB spec is limited to only 6 keys, and that's why it's not favourable for gaming input devices likely to press more than 6 keys at once.
*no competitor promoting*