As an ex-pat American from Colorado that's now living in Britain for 5 years, I feel compelled to speak up. Product design has many elements which effect quality, and very few companies manufacture in-house (the most notable exception might be Frost River packs.) Many of the brands we all know and love, including my US-centric favourites (NorthFace and Patagonia) are manufactured overseas. What clothing companies bring to the table, and what impacts quality the most, are initial product design and specification; material selection; and most importantly, factory selection & production management. No company can prevent stitching problems. These things happen, and the only thing a company can do is to catch them before they hit the market. A company, can, however, be more proactive in choosing a factory, but that process is not a trivial one, and only larger better-funded brands have the development budget to do so. Smaller companies inevitably have problems and are always looking for a better factory.
I for example, count among my bullet-proof kit a NorthFace tent, duffle and water-proof shell; a Patagonia waterproof flyfishing jacket, and a couple of pairs of Asolo boots. Unless the Bad Thing happens, I do not expect to ever replace this gear. Coloradans are notoriously hard on our gear. We ski, fish, hike, camp, raft, cycle and even invent new and crazier things to do in our kit. We're shameless gear-heads, and have no problem spending hundreds of dollars on something that will last a long time.
When I moved to Britain I was stunned to find that despite the global nature of the brands (Patagonia and NorthFace, for example,) there were entirely different products here. I innocently assumed that a gear-head was a gear-head, and that British gear-heads would appreciate and use the same brands and gear that I had. I was surprised to find otherwise. To be fair, I'm rediscovering the beauty of using surplus gear. That stuff is generally built to last and costs much less than their commercial equivalents.
But is European better or worse than North American clothing? I don't think so. I believe that there is a similar variance of quality, price and selection across both markets and the trick is to determine first which market sector you occupy and then to find the brands and products that occupy the same space. I for example, prefer the advantages of long-term quality and prefer to research heavily before forking out a lot of cash for a product that I will never have to replace.
This is all getting too long for one cup of coffee…..