Back to the basic, put all 3 on your wrist and see which one feels the best.
For a start, out of the three, i think Rolex is a good choice.
I personally do agree with Spiderboy, if you opt for Rolex DJ line, why not have a try with the 36mm, it has the elegant look, and best comfort of not being hefty like the bigger brother. As for me, the 36mm DJ with chapter ring engravement or Sub C will be my choice for the Rolex, the reason i like the Sub C, other than the good classic look with lotsa modern tech improment, the solid bracelet with quick adjustment is to be lusted, try it.
Between Zenith el primero or IWC Portugese, i will opt for Zenith open heart, i could just stare at the watch extra large opening of the "heart" movement and the propeller shape second counter, without knowing the time! Well, as for the IWC, the extra large case back sapphire window and rotor, with a slim case, is what i would admire.
Well, just my tiny opinion on your 3 selections, good luck!