the steel blue face is the iconic Nautilus and you probably have seen posters and magazine advertisements in alot places. If your lifestyle involves outdoor activities or a dip in the pool, the steel would be ideal.
However, I find that the precious metal versions offers much more elegance and feels much 'softer'. You need to put them side by side compare if possible. Both versions are handsome but the rose gold is warmer and perhaps dressier.. and I would not take it for a dip nor cut the grass in the garden wearing it.
Can't go wrong with either one. Good luck with your choice.
Cheers !