You can't tell which sat nav it is by looking at it.
The professional version has a 8.8" screen and a HDD. The HDD stores the maps, and may also be used to store music, contacts, etc. The single slot is a DVD drive, and plays both DVDs and CDs.
The business version has the same screen BUT only uses 6.5" of it, ie there is a 1" blank strip down either side when in use. There is no HDD. Maps are stored on internal memory (eprom I guess); you can't store music etc. The single slot is a CD drive, not a DVD.
They use the same controller.