Window offer evaluation - Is it okay like this?

Thanks for the comparison numbers.
So you would rather go with the following option:
Take the window including the lift-and-slide door from the provider BUT have the blinds offered by another service provider?
As I said: purely in terms of the quality of the profiles and the quality of the window service provider, I am convinced.
And according to your statements, the prices for the window and lift-and-slide door are apparently OK.

But your question is completely justified.

I give this hint mainly because this single advantage of Quadro XP over Quadro P is easily overlooked.

BUT have the blinds installed by another service provider?

In my perception, the everywhere uniformly too high price of blinds (if they are not overpriced, they usually are no good) is simply the penalty for people who drill their windows into huge blazing sun entry gates without having ensured natural shading in the garden, under the motto "perversely costs extra."

Lift-and-slide door 2300 x 2125, laminated on both sides

For lift-and-slide (and front) doors, there would be nothing for me to laminate because I would never ever take them made of plastic. Frugality is not so cool that one absolutely has to "save" at the very wrong end.

For lift-and-slide (and front) doors, there would be nothing for me to wrap because I would never ever take them made of plastic. Stinginess is not that cool that one absolutely has to "save" at the very wrong end.

Are you rather averse to plastic here because of the risk of the frame warping? Would aluminum be better from your point of view?

Would aluminium be better from your point of view?

Aluminium is, from my point of view, the most suitable material (and significantly more economical compared to high-quality wood). In my opinion, and I don't care who thinks that's snobbish, plastic is an inferior material for windows. But I let everyone have their bliss, believing they have found a nice way to save money. I recently explained this in detail:

Are you rather averse to plastic here because of the risk of the frame warping?

You can put it simply like that, even though the plastic profiles have "steel cores" integrated. In lift-and-slide doors, the weight presses down on the sliding rail and the rollers, where in the budget segment savings are made. Cheap lift-and-slide doors become "stubborn" more quickly – the bodybuilder might not mind, but his delicate lady probably will. As for front doors, their frequent high stress compared to less frequently moved elements is mostly underestimated. A lot of price is also in burglary protection, so an "cheaper" frame hardly matters in the end. Mind you: "this is what the dentist recommends to his family" – my time as an aluminum window manufacturer is over; personally, I don’t lose anything today from a customer who wants to buy plastic.

But I wish everyone their bliss, to believe they have found a nice savings approach.

I also like to learn something new.

You mention in the linked post that plastic windows of "better" quality only cost 20% less than those made of aluminum.

If I now take an average of the offers I have for plastic windows (€25,000), the equipment with aluminum windows would cost me around €31,000 in the end. So I already save €6,000 with plastic windows of good quality. As a saver, I would now go for lower quality plastic windows and achieve a saving of 30%?! Then we are talking about almost €9,500, which I would also borrow from the bank and consequently have to pay interest on. Over 20 years at 2.2%, that would already be €11,750.

Now I have to ask myself how many of my elements will probably break over the years and what it will cost to replace them at then current prices. Assuming €21,700 (30% less than aluminum) and 2% inflation, the same windows would cost me about €32,200 in 20 years. In relation to my initial savings, about 36% of my windows would have to break in 20 years without me financially regretting the decision against aluminum.

If I also consider how much I will still cling to my windows from 2018 in view of technological progress in the year 2038, I simply cannot see the argument in favor of aluminum.

Curiously, I have an offer here from a manufacturer who gives a 20-year warranty on their plastic elements (including the lift-and-slide doors) but still prices them in the aforementioned mid-range. Is he crazy? ;-)

No manufacturer has to be stupid to offer such a warranty (although of course the question is what exactly is being guaranteed). These things will not break apart in the sense of falling to pieces.

Aluminum windows from about forty years ago are still worth their price today, as they still look like new (technically, they have probably been readjusted and mushroom head locks retrofitted). Even I can’t tell plastic windows apart from a normal viewing distance as long as they are young. After about 15 to 20 years, however, you can see on their surface that the plasticizers have evaporated. Then you can re-laminate them and they look good again.

Aluminum windows from about fifty years ago are still in great condition today, but that doesn’t help them: they were constructed differently back then (they lack a thermal break between the inside and the outside), and they were usually only available brushed or anodized, which hardly appeals today. The joy that outweighed their additional cost back then is therefore gone.

But it is not a problem that I am not moved to consider plastic good enough, and you are not moved to judge it the same way. More important is that we have both explained our views and every reader can now judge for themselves which "faction" they want to join. The commonality of all truths is only that none of them is the only one ;-)