I'd say the SD card is certainly "worth it" - it has 100 extra sounds on it, many of which are corkers.
The only thing which remains a source of inconsolable irritation for me is that Marcus didn't include the M400 String Section sound on it, which happens to be my favourite sound! This is particularly ahine as there was space for it, as a couple of the other sounds were duplicated! Ho hum.
David