To be honest, with regard to the sophistication of design and fabrication, Arc'Teryx has no equal. I was working as a buyer in the late 90s when they introduced their first few pieces of technical outerwear and on their first shot out of the gate, they were 10 years ahead of the competition. They still lead the pack.
Most consumers probably wouldn't notice what makes Arc'Teryx genuinely amazing. In some cases the refinements are so small, the insanely sophisitcated engineering and manufacturing elements are easily overlooked. For one example, their taped seams are incredible, but does anyone really notice seam tape?? That's just one tiny, overlooked detail that sets them apart. Not only do they strive to use tiny seam structures (1.6mm instead of an industry standard of 6.4mm) the tape they use to waterproof those seams is equally small. Imagine how hard it is to accurately lay down a skinny piece of tape instead of the big fat ribbon of tape most brands use. The Arc'Teryx tape is also cut with such precision, no two intersecting pieces of tape overlap. That blows my mind. Overlapping tape adds bulk and weight equal to putting a quarter in your pocket. Does that translate to not making the summit of your climb? No, but it speaks to the unparalleled attention to detail Arc'Teryx uses in their products.
It's also worth pointing out that Arc'Teryx is so innovative, they frequently invent their own zippers, fabrics and manufacturing techniques. They're also not afraid to simply sit down and do some things by hand. I'm still amazed how they make their Warp Strength Technology harness components. That's hand crafting meets aerospace sophistication, all in the name of saving a few grams.
I could go on. As a professional buyer, I spend several hours a year listening to tech reps and product designers sell me on why their products are the best. The Arc'Teryx designers are speaking an entirely different language.
Now, does this make their products perform 20-30% better to justify the price? That's up to you to decide. It is expensive. It's also cut pretty lean, so it may not fit everyone. I don't think every product they make hits the mark, but that's measuring those products against their own measuring stick.
Excellent stuff.
There's a level of simplicity to Arc'Teryx that you can also find with other top tier brands. I would look to RAB as another option. I've become a huge fan of that brand. I also really like Sherpa clothing.