Zowie FK2 or ZA series?

[185db]

I've been looking at these mice and I can't decide which one to get. They seem to have the same internals, it's just a difference in size. FK2 and ZA12 are very similar, while the ZA11 is a little larger and the ZA13 is a little smaller.

http://www.zowiegear.dk/shop/mice-512c1.html

Anybody have experience owning any of these mice?