I'm using them on my acoustic guitars (85/15 Bronze on a Jay Turser and PB on a Yamaha) and doubt I'd feel better off with anything else on them

I use different makes on my other acoustic instruments. Picato on a mandolin (mine needs ball end and they seem to be about the only one making a decent PB set) and Eagle-newtone for tenor banjo (in part as they offer "custom sets" where you can pick your own gauges and I tend to go heavier bottom end than std sets do).

I don't know, but on the wider subject of strings, I've long felt different things suit different player/instrument combinations and it's unlikely that there is a one brand suits everything...

On the more specific question. I've not noticed any quality control problems with D'Addario,