And unless you know what's going on "under the hood" well enough to either evaluate their code or design a real-world test that you can perform in an empty parking lot…you're left to decide based on what Mercedes says. And they're never going to say "our system can't detect the cause of a skid…it just reacts based on detecting the speed wheels are spinning and assumes the driver is completely incompetent."
Some of the systems are great. There's no reason a car sold today shouldn't have ABS: the driving techniques required to get similar performance out of non-ABS brakes are very skill specific and time-intensive to develop. It's not worth it for >99% of drivers. And there are "good" traction control systems. Subaru's computer-controlled differentials in their AWD system are pretty good. But that system isn't capable of making a mistake as bad as the "active braking" systems that are coming out.