I've never experienced bad strings from D'Addario. I use them on everything from fretless bass to acoustic guitars, to mandolins, and have for 30 years or so. The sealed packaging makes for a long shelf life, but even the unsealed bulk spools last well.

I have seen strings that masqueraded as D'Addario but definitely weren't, not sure if they were counterfeit or just look-alikes. The colour coded ball ends weren't quite the right shades.

The DR coated strings are okay, got them on the bouzouki at the moment, but I don't often use coated strings except on instruments that don't get as much use and require pilfering from two sets of guitar strings to restring...they gotta last.