My wife and I have ridden Speedplay Zeros for 10 years or so on a dozen bikes. I've never accidentally unclipped from them. In fact, as the cleats age, I find it increasingly difficult to get in and out of them - that's usually my tell-tale signal I need new cleats. I've also raced on the track with them - regular Zeros and Track Zeros - and have pedaled at more than 200 rpm on the rollers with them.
The pedals do require a bit more maintenance than Looks. You need to routinely grease the bearings - you do not need to buy expensive Speedplay grease. Rather any basic bike grease works, and a cheap syringe from a drug store is sufficient for pushing it in to the bearings. The bodies do wear out over time and need to be replaced. When the R and L are gone, that's often a good sign it's time to replace the bodies. Speedplay sells replacement bodies, but in my experience, it's better to just replace the whole pedal. Removing the bearings from the old pedals is kind of a PIA. I've also had issue with the screw that holds the bodies on getting locked in place. If weight is a concern, you can buy CrMo spindle pedals then buy $35 ti spindles off Ebay and sway the bodies over.