based on the rave photozone.de reviews i went ahead and bought one in june - with a price tag of ard. 300 euros not too much of a risk...
my 1st hand impressions:
good build quality (metal barrel), good haptics (smooth focus action).
resolution really quite good (didnt scientifically test it), never bothered with distortion correction (landscape and street mostly)
i felt vignetting at 2.8 was quite extreme though - yet OK at smaller apertures
online info available on this lens did not seem to mention two aspects though:
1) significant focus shift when changing aperture - as this lens is 100% manual
(including stopping down aperture) this took a bit to get used to and compensate for
2) the distance markings on the focus ring of my copy were wayyy off -
i used adhesive tape and marked i.e. 1m / 2m / 3m / 5m / infinity at two diff. apertures to work with.
if you are not in a terrible hurry resp. use i.e focus work arounds i found it to be awesome value for money.
i also put together a comparison of samyang 14mm to EF L 14mm
and the samyang 85mm vs. canon 85mm 1.8 based on photozone.de review data - see attached image
translation & legend: green boxes: samyang better than canon, red boxes: vice versa.
vergleich = comparison, aufloesung = resolution