As promised few posts above, I just wanted to share my thoughts and impressions about the JF V5 vs ZF 15400. JF is with grey dial meanwhile ZF I got the blue dial, even if I am more a "grey dial" man LOL.
Anyway, first impression, both are nice, from a distant perspective they could look very similar, but in fact they are not.
I have tried also to swap the case backs but it's not possible. The JF watch has a completely different construction. The movement looks like it's sitting lower inside JF compared to ZF, and both case back and bezel are thicker on the JF. The thickness of the JF case back is easily noticeable, meanwhile the bezel you really have to compare them side by side to notice the fact that ZF one is thinner. Also the case on ZF is slimmer and so is the bracelet. This bring to a weight difference of almost 20 grams: my JF weights 172 grams and ZF 154. It's not very much but you could feel it when wearing it.
Speaking about wearability the ZF is a step over JF imho, probably because if's slimmer and also (maybe) because of the weight difference. On the other hand, the bracelet on the JF is on the watch I have, better refined, feels more solid and the clasp, that one yes, a step over ZF. ZF clasp on my watch feels and looks like it has not been refined, I would defintely try to swap them and put JF one (the best one imho) on the ZF.
Another thing that is more relevant for me and gives a "more like to gen" appeal to ZF if the rehaut height. On the ZF the space between the dial and the xtal is imo lower, and this makes a huge difference. It's not noticeable in the pics, but you can see it when you have them side by side. The JF now looks more like the old fake chinese watches who had a huge rehaut that simply make them funny to look at....don't get me wrong guys, we are not at that bad levels, but here the ZF is also clearly the winner.
For what i can feel, for me the best mod would be ZF complete case and JF bracelet.
I won't go into too many details, let the pictures speak for themselves. Enjoy and sorry for the bad quality of my iPhone 6 camera: