By the time you get the Nexus, GS3 would've been released.
Also, nexus has a shittier camera, and really the big difference is the ICS. You can always get skins to match or just wait for the S2's ICS update. Lastly, there's NO microSD card slot. No extra memory? Fck that shit.
Also, if you really want to rub it in, tell your friend to get quadrant benchmark. You will see how S2 REALLY blows nexus away in performance. My T-mo S2 stock got a score over 4000. From what the internet has shown, nexus is stuck around 1700.