I won't be buying the s602 update. The device I have now already runs all the games the new one will. And it doesn't look like the screen resolution is improved, though capacitive would be nice.
The s5110 revamp looks sort of nice I guess.
I'll probably just get the s7800 or if a s5800 comes out i'll get that.
Right now I have sitting next to me a 4.7" smart phone, a 7" tablet, and my s602. The s7800 interests me because it has an excellent screen and could function as a tablet as well. But why replace my s602 if it does it's job perfectly minus the battery and can't replace one of the other devices.
The only thing that could get me to upgrade it would be better gaming functionality. So unless I can play all the other n64 games on it that currently don't play well or start playing nds games, it's sort of pointless. And at this point there aren't any android games I would want to play on it over my nexus devices.