I have a like new Samyang 24mm F1.4 with Nikon mount (I have a Nikon to Canon adapter I can throw in).
I find I am using my 14-24 mostly and have moved to mirrorless. Its a very sharp lens and is clean of false colour around F2, definitely by F2.8. It would make a good nightscape lens or time lapse lens. In daylight its a good landscape lens.
I sent one back to get a good copy. This one is very good.
On ebay they seem to go for between $617 to 658 or so:
http://www.ebay.com.au/sch/i.html?_o...+F1.4&_sacat=0
with the risk of getting a not so good copy.
This one is AUD$550 including Oz postage and Canon adapter.
Sample photo:
http://www.pbase.com/gregbradley/image/149391334
Greg.