Distortion test results have been added to the Venus Optics Laowa 12mm f/2.8 Zero-D Lens page (a full review is planned).
I don't often dedicate an entire post to just distortion results for a single lens, but ... I thought the results for this one were remarkable enough to highlight for you. If you are looking for an ultra-wide angle full frame lens that keeps your lines straight (attention architecture photographers), this one should have your attention. Here are some comparisons:
Venus Optics Laowa 12mm f/2.8 compared to Canon EF 11-24mm f/4L Lens
Venus Optics Laowa 12mm f/2.8 compared to Sigma 12-24mm f/4 Art Lens
The Venus Optics Laowa 12mm f/2.8 Zero-D Lens is in stock at B&H.