Wait, when did you pick up the Rokinon 14? And how does it compare with the Voigtlander 15mm? I've never considered it too much between the size and mustache distortion...
I didn't. I borrowed this from a friend just for this trip, since I sold my Voigtländer 15/4.5 a couple of months ago. The Samyang is definitely the worst of the two. It can't beat the almost-inexistent distortion and the fantastic sharpness at the centre of the Voigtländer. Maybe this copy of the Samyang had some kind of issue, but even at f/8 I was never able to get things as sharp as the Voigtländer wide-open. If I ever get a A7RII, I'll most likely then grab another Voigtländer 15/4.5.
I love the not quite symmetry of this, makes it even better than if it was perfectly symmetric in my eyes.