The samyang 35/1.4 is what I've got, it's optically a very nice lens, but the build quality seems to get worse every time i use it.
Not that it's falling apart, i've used kit-zooms that felt looser and wobblier. But for a start, it's really hard to get infinity focus (sometimes it tops out at 100m or so), I've really got to pull it right to the end (nb: this could very well be related to the fact that it was 2nd-hand and I had to do some minor repairs, specifically to the focussing system at the infinity-end, I'd hope that a new-bought would be better).
Also, I've read about the new 24mm in a review that when changing focussing direction there's a mm or two of travel before it starts changing focus. This is what my 35mm does, i've never read that in a review of the 35 though (again, it could very well be related to my repairs). If it also happens on new lenses, it could get a bit annoying, especially on video.

But there's no going 'past' infinity like on my 15-85 and 70-300L, even just 1mm past infinity would be enough to focus it nicely, even with my problems.

On the plus side, undo a handful of screws and you can de-click the aperture (there's no stop between f/1.4 and f/2.0), could be good for video (any manual aperture is good for video i suppose).

As for the 14mm and 85mm, never used them. From what i've read the 14mm is as sharp as the canon L in the centre, but borderline-fisheye barrelling (ie landscapes fine, cityscapes not). And I picked the EF 85/1.8 over the zeiss, sigma and samyang 85/1.4, no regrets (the nikon 85/1.8 should also be nice), for me in that length for kids-running-around-portraits the AF was worth more than the extra bit of a stop.