What are the differences in quality of shower cabins?

Hello, the topic of price differences comes up here quite often, but I don’t have a proper explanation for our specific example. At the moment, for our new build, we are having our bathroom planned by the general contractor. For the shower enclosure, we have chosen one with a corner entry and pivot doors. Our general contractor offers us the HSK Atelier incl. installation for 1,300 EUR. On the website of Berstein-Badshop, you can find an almost identical enclosure but from an unspecified manufacturer for just under 400 EUR. BOTH have lift/lower mechanism, 8mm ESG glass, and flush hinges. How does such a large difference arise here? Should one expect significant quality differences? If yes, which ones. And what would one possibly need to budget for installation by an external plumber?

The problem is finding the craftsman. Let him calculate two men at three hours each, that makes 240,- net. But he won’t do it because he wasn’t allowed to sell the door. He would have earned really well from that, no matter how small the trade is, it brings in more than just work. And since he probably has his order books full and you are not an old regular customer.... Maybe you’ll find a one-man caretaker service who you trust with this. Then it could work.

Ok, good to know. But where could the quality differences be here between the no-name product and HSK?

Fittings, rubber parts, rollers, profiles ... all of these can be manufactured in different quality levels, just like with all other products... a shower enclosure is no exception here

How does such a big difference arise here?

Apart from the respective component quality, you are comparing a pure delivery price (including shipping?) with a price for delivered and installed and the garbage is also taken away.

I also believe that the price difference hardly arises from differences in quality. The 1,300 euros probably includes, besides the mentioned points, also the measurement and the warranty. Added to that is a small "one-stop-shop surcharge," and then it more or less fits.