That doesn't address the question. The nexus S was and is a bear to use. Your thumb can't cover the width of the screen and the usable arc in one finger operation doesn't give you 100% coverage.
It's a matter of personal preference. Also depends on how big your hand is. I am, for instance, not satisfied with my 4 inch screen and selling my Nexus S to buy a 4.3 inch android.
Speak for yourself. My S' screen is no match for my mighty bear claw.
The Nexus S has a 4" screen. The Galaxy Nexus is 4.65".
Yeah, it's physically bigger. Nexus S is 124 x 63 x 10.8 mm, Galaxy Nexus is 135.5 x 68 x 8.9 mm. (Both probably with an asterisk on thickness, but...)