Levis aren't discussed here because it isn't the right place.
I am sorry but Diesel & GStar aren't on the bottom of the barrel when it comes to premium denim.
Balmain probably isn't worth it's retail price, it is a luxury item and one of the most expensive brands at that. You really pay for the design. I mean quality is still there but you can find jean of the same quality for half the price but once you feel the denim, you can see it is thick and well made. You also really can't find the style if that is your thing. I mean Rogue made some that looks like Balmains moto jeans, I got them for around ~$80 but quality isn't on par, not even close. I have many jeans/pants on rotation so it doesn't got much wear but after 2-3 wearing on te Rogue, the rivets were falling off and it looks like it'll rip instead of stretch.
Dior is much cheaper so the quality to price ratio is much closer but Dior provides another example of paying for something you do not find on any other brands out there, the cut. I still find the cut unique on the Diors and if that is your preference, then the cost is worth it. QUality isn't something to sneeze at either, at least the Made in Japan ones, I read that Made in Italy versions quality is a notch below but still good overall.
As for Dior & Balmain, I found Balmains denim thicker, heavier and quality seems a bit better, does it reflect the 3x-5x it's cost in comparison to Diors? Likely not you will never find moto style jeans with Diors. Keep in mind that the Balmain I handled might be thicker for that season, there are some thinner ones too with distressing and rip. In the end, you really just have to weigh-in your options and get what you like/want.
and when I saw the price on luisaviaroma I was like :x $6790
