Acne is a label while Ralph Lauren is a parent company of many other labels. Putting RRL or RPL in the same category as Polo isn't exactly accurate or fair. RRL is one of the few exceptions in the industry where a fashion brand actually has denim head-quality products, but then it makes sense when you consider their targeted customer vs. Acne.
With brands like Acne, you're paying for the name and the cut. Nudie has a lot of variety but you pay for that premium. So are fashion brands up to the same quality as a denim company like Iron Heart? They're not marketed as such and they're not priced as such, so no.
And are three pairs enough for what? Most on this thread have 5+ pairs and several in the double digits.
I guess I didn't make my point well enough, I knew that Iron Heart would be superior to the brands I mentioned - but I wasn't sure how drastic the differance was and if they are worth an extra £200 for jeans that will not be my go to pair. From your response it seems you think they are worth it - So I will do more research into other iron heart cuts.