Europe has had start/stop systems for decades so there should be some longevity data related to start/stop systems and their impact on the engine. Some OEM's have "smarter" systems than others and thus do not stop/start unnecessarily. I can state unequivocally that Mercedes and GM (in the Netherlands) have better systems than some of those in the US. The system in my Jeep (FCA) is not very smart and stops far too often, but with that said, I have seen an MPG improvement when using start/stop versus not no matter which OEM it is.
I have a Tazer Mini that I will be installing at some point that will turn off start/stop on my Jeep so that I do not have to remember to shut it off each time I get in it.
I had a FCA rental several years ago with their start/stop and I agree, it shut off very quickly after stopping. In fact it would shut off while I was parallel parking. I did turn the system off once I figured out how to.