Except that the same retailer, BuyDig, had the 14mm lens alone for $299 only about 9 days ago...and it has sold for even less in the past via the big camera retailers, and I think also Amazon. I'm heavily considering buying one.
As for the Samyang 24mm, I don't doubt it's a fine lens, but I feel the Sigma 24mm f/1.8 is by far the better buy at only $549 (during the holidays it was well under $500)...with autofocus, aperture control, etc. Yes the AF motor is not silent, but it actually works fairly well and quickly...even in servo AF mode. Optically, I would definitely put it up against the Samyang any day. Even wide open it is quite sharp in the middle 60% of the image, and in the middle 40%, its coma and CA are also relatively low. Towards the periphery...no. But I doubt it's much worse, if any, than the Samyang (or even the pricey Canon L for that matter!). The Sigma also has very smooth bokeh...smoother than my Voigtlander 58mm f/1.4, anyway. When closed down, the Sigma is quite sharp everywhere with artifacts also on the low side...everywhere. That's saying something. (Obviously the 14mm Samyang/Rokinon is optically superior to all of these, but it is a unique lens and unique value, comparable optically, at least "resolution of detail"-wise, to the $3000 15mm Zeiss, as well as the much loved Nikon 14-24 f/2.8 zoom. Color rendition-wise, the 14mm Rokinon does not come all that close to the Zeiss. But that's a huge price differential to pay for some color and a bit of contrast, in my opinion).
The Sigma 24mm f/1.8 also has less barrel distortion than the Samyang 24mm f/1.4, I believe. That said, I am slowly trying to sell this Sigma (not lowered the asking price much yet), because I've spent too much on other lenses (recently bought the 70-300L), and just don't use it often enough. I mostly bought it for night sky and astro type imaging (believe it or not). As long as the object is in that middle 40%, it can comfortably be used wide open, or close to it. What it is best at though, is MACRO WIDE ANGLE photography. It is mindblowing with this, actually. Especially considering you have such a big choice of controlling the depth of field, at such a close distance with very good magnification. I do hate to let it go...so if I don't get a high enough offer, I may wind up keeping it after all. I've definitely not done enough macro images with it, and would like to do more of the spring wildflowers. The color rendition is better than my only other wide lens as of now, the 24-105L. And the amount of barrel distortion the 24-105L has, at 24mm...is actually absurd. If it were a 24mm prime lens with this much barrel distortion, I think they'd have a hard time selling it. Fortunately though, obviously it's a superb zoom lens, and a superb value overall (not trying to be captain obvious on that one, sorry...haha!)
I can see why people desire the 20mm f/1.8, because of its unique wide angle, big aperture, along with the macro ability. But optically, neither it nor the 28mm f/1.8 version, compare to the 24mm version. It is sharper everywhere. I did the research, looked at the test charts.
It's entirely possible that Sigma will produce an "art" version at 24mm, but that lens will most certainly cost more than $1000. And at this point, it might be 2 years from now before it's available, if not longer.
One last note on Sigma. What interests me most with them now is the new sensor in the new DP series cameras. The body looks almost ridiculous, but optically...it may very well exceed the D800's ability (even though it's a crop sensor!), at least in good light...obviously not in poor light. Also I doubt it will approach the D800's dynamic range at low ISO (so don't jump on me for that!)...I'm just referring to detail resolution via its stacked pixels, that don't need no stinking bayer array!
Sorry to those who didn't like to read about Sigma, I'm not trying to hijack the thread or anything. I just do feel it's necessary to discuss their 24mm lens, when considering a manual-only lens like the Samyang/Rokinon. Samyang's "T" series lenses meant for cinematography, do look quite interesting (and no AF is needed)...if the use scenario is video.