At least we know what to expect with the mls
SCV polish at 50k, replace at 100k, HB at its descretion and......boring...no belts, new engines, injectors....
Even the fan & ac belts would probably lasted to 200k, as didn't look worn when I replaced them.
The harmonic balancers must just be a bad design, or batch. My Power bond replacement ( touch wood) has more than double the kms of the original and is not showing any signs of deterioration.