I really liked the sound of the Irix 15mm and 11mm when I was in the market for a WA Astro lens, I ended up buying the Zeiss 15mm because it has a manual aperture ring.
15mm Review https://www.wildlifeinpixels.net/blog/lens-review-irix-blackstone-15mm-f2-4/
11mm Review http://www.ejphoto.com/Quack PDF/Irix 11mm Review.pdf
Make sure you buy from a place that has a good return policy.