The DA560 is a joke, at least to me for its price and image quality.
I myself see no reason to buy this lens for its prce whilst image quality is inferior to Sigma 500/4.5 , FA*600/4 and FA*250-600/5.6
I owned the Sigma 545 before the launch of DA560. When DA560 comes out, I once thought whether I should got it because of its WR and DC, however the image quality stopped me for paying such a price.
Eventually I decided to got the FA*600/4 after the launch of DA560,
Here is my pics with FA*600/4
http://www.dchome.net/forum.php?mod=viewthread&tid=1183098
Finally, after deciding to have a Safari trip within these few years, I sold my FA*600/4 to a friend and got the FA*250-600/5.6
http://www.dchome.net/forum.php?mod=viewthread&tid=1230583
My comment of the image quality re DA560 which is not good enough is based on the Pentax Forum Review, some web photos of Japanese user and Taiwan user and also a Chinese review by a Chinese user.
Sorry to say, I think if I am a bird shooter and have money to spend, I would rather buy the Sigma 500/4.5