A generic OBDII scanner can only access a small number of systems on the car, relating to the engine and transmission only.
The MB-specific OBDII scanners (Carly, iCarsoft, Autel, Launch, etc), can access many other systems, such as ABS, airbags, climate control, central locking, etc etc, and this is in addition to more-detailed diagnostic of the engine and transmission. On a 2007 car the MB-specific scanners should be able to access around 20+ additional systems.
However, a generic OBDII scanner will cost around a tenner, while an MB-specific scanner will cost upwards of £100.
Down to you which one you buy.