Some people says that it's equally sharp with PC-E but struggles from flare much (true) and has more distortion.
I have Sony mount version and shoot much, see:
http://flickr.com/photos/qwz/tags/samyangt-s24For Sony SLR it's only 24mm option. I think i'll migrate to E-mount and buy Canon TS-E, may be 17mm first.
Anyway, Image quality is nearly excellent over unshifted frame and not more than 6mm shift|rise.
Flare can be problem with sun or strong light sources hitting front lens outside frame.
Distortion can be easily corrected on Capture ONE Pro. Colours are nice but with more green than my other lens (Carl Zeiss, Minolta and Sigma).
Build quality is moderate. After 6 months of use mine copy's infinity focus shifted first beyond Infinity mark and few days after beyond and lens movement.
Local repair fixed it w/o a charge in 9 days.
Also it has two design flaws:
First, they forgot to implement both direction rotation and diagonal shift+rise is possible ONLY for top-right OR bottom-left.
Second, on my Alpha a900 for horizontal frame rise is limited to 10mm 'cause of protruding pentaprism.