Its unique 'Dual SIM Always on' feature allows you to receive calls on one SIMnumber while taking a call from the other, ensuring that you can manage both personal and work commitments without ever missing a call.
Interestingly (at least for a flagship), it appears to be a dual-SIM version, with the mono-SIM version apparently picking up model number GT-i9500 -- a number that would fit in with the series so far.