I spoke with several divers wearing DUI suits with zip seals this past weekend, and only one of them was happy with them (the wealthiest one, I'll note). They each acknowledged that they had had dives saved by them a couple of times, but the expense is VERY high, and more significantly, the latex on the zip seals seems practically designed to fail. It is VERY thin and fragile. No wonder people like them so much... they keep failing, and then they get to pat themselves on the back and think they did the right thing and gee isn't it great how easy they are to replace! If they had regular seals, they would have been beefier and probably wouldn't have torn in the first place. So it's a balancing act... weigh the possible (and probable) tears and expense (but saved dives) against less likely tears and less expense, but potential missed dives should an accident happen.