market and price differentiation, if you don't need more features and a more powerful guide number, one can buy the lower model.
sammedia said:Seen like the new SB600 is bit weak as compare to the SB800.
SB600- GN-30/98 (ISO 100, m/ft), 42/138 (ISO 200,m/ft) (at 35mm)
while
SB800- GN-38/125 (ISO 100, m/ft), 53/174 (ISO 200,m/ft) (at 35mm)