I got the Bell and Howell name of the Samyang for $279 or something off Amazon from Beach. It has gone up to $320 or more since. Don't spend more for the other names, they are identical!
The IQ is amazing. I am blown away by how sharp it is. It may be the sharpest lens I own honestly, not even joking. At 100% the details are insane. It has some distortion but easily corrected in LR with profiles available online. I set the lens at the hyperfocal distance and f/8 and don't worry about AF. All is in focus anyway.
Best value lens I have ever used. Incredible IQ, no CA, good flare resistance and great build. For under $300? I would never consider the 14L anymore.
The only bad part is that the focus scale is generally wrong on all these lenses. So you must rely on live view focusing or just using hyperfocal distances.