That's about the graphics... So now let's look at the actual CPU speed of the 900 MHz dual CPU (iPad 2 and likely 4S as well) vs 1,2 GHz dual (Galaxy S II), I think the S II has a lot bigger chance to win..
Yes, If we compare the A5 in the iPad 2 against the SG2:
Pretty sure the benchmark for the iPhone 4S will be almost the same.
And really...Will the A5 be any faster than the 1.2GHz Dual core in the S2.