Originally posted by Driline +1 for the FA 43 because it has sharpness AND bokeh, rendering and contrast.
And it's also the cheapest of the 3 amigos. You should be able to pick up a nice used copy for under $600.
The 43 is also the most finicky and hard to master of the three (I own one). The guy asked about DA Limiteds and said that the 15 is too expensive. The FA limiteds are MORE expensive.
You said wide was the way you wanted to go. Give you have ruled out the 15, the 21 seems the best choice give your own statements. It is, of course, your choice but the 21 is wide, sharp, and a solid performer. I own the 70 and have owned the 40 and on APS-C neither is "wide" by any stretch of the imagination.