Geez, I'm actually putting my money where my mouth is: last month I broke down and bought the Zeiss Touit 12mm f/2.8 for my a6000 (and now my a6300, too). Good thing I don't have a full frame e-mount camera yet, or I'd probably have to cough up the dough for the field of view equivalent Batis 18mm f/2.8. Sigh. Gear porn at its finest, from Las Vegas (NAB 2016).
NAB is always exhausting, but always worthwhile, too. The field of view on an 18mm lens is second only to the FOV of 24mm as my favorite wide angle focal length, and a quick peek through the viewfinder shows the usual Zeiss hallmarks of sharpness, contrast and minimal rectilinear distortion(I didn't see any, but hey, it's a few seconds on a convention floor).