I don't care if it is JF V2 or V5 or even the latest ZF. The simplicity of the RO 15400 is pure sexy. Black dial, white dial or blue dial are all superb.
I think many of us are so good at comparing it that we get a bit too anal about the slightest difference. Keep in mind, most folks won't be able to tell the difference.
I recently acquired the JF V2 serviced and thinned. It's a great watch and my new favorite.