In my opinion, the problem with the MB radiators (and it is quite common) is probably not with the type of coolant that is used, but more probably a factor of age of the radiator plastic, the torque used to tighten the clamp, and the width of the band on the clamp.
I suspect that if current owners of older plastic-necked radiators would change the clamp to a wider one than that which came with the car, and used caution when tightening the clamp, they would extend the life of the neck. The newer necks have a metal (brass?) bushing inside of the neck in the clamp area...I haven't heard of these types breaking.
My original radiator broke in the same location shortly after I purchased the car (car was 9 yrs old). I was not comfortable with just putting the hose back on the stub and driving for very long. I found a new OEM radiator (with the neck bushing) costs only about $245 (W124) and I sleep better with the peace of mind it gives me.