I had my one and only near death experience (while diving - we won't review my aviation past) due to a cracked regulator case. My buddy, a PSD, was at 130' when his small cracked decided to become a big crack. He inhaled a bunch of water, got into an interesting cough/gag/inlae more wate cycle and panicked. He proceeded to slam me into the silty bottom several times to get my attention and the low viz went to no viz. I managed to get behind him, drag him out of the silt cloud by the manifold assess the situation and get him to the surface with some additional assistance. He would not swap regs due to his panicked state.
It could have gone much worse for both of us. I no longer dive with large weightlifting PSD's with cracked regs.
The dealer cost for a new S600 case is in the $10.00 range, so even with a 100% markup for those dealers who mark up parts, it is not an expensive fix even if it is not covered under warranty.