Advantages and disadvantages of different ventilation systems

With my Vaillant, this is subtly built in by the manufacturer as there simply is no power switch. So neither a rocker switch nor one in the software menu. The only option is to unplug or remove the fuse.

In my Vaillant, this is subtly built in by the manufacturer by simply not having an off switch.

That is well thought out by the manufacturer. When comparing systems, I will pay attention to this criterion from now on. Does any of the experts actually have some kind of feature checklist that can help with the selection? So far, it’s always about "yes" or "no" – but those who decide on "yes" are not really much further ahead either.

Does any of the experts actually have some kind of feature checklist that can help with the selection? So far, it's always about "yes" or "no" - but those who decide on "yes" are not really much further ahead with that.

There isn't one explicitly. But plenty of tips online (divided into decentralized or centralized). Any feature that goes beyond "automatic ventilation with adjustable strength" is nice to have, but doesn't change the function of the ventilation systems. Only with decentralized systems would I add pendulum ventilators vs. crossflow heat exchangers as a key point (although the latter are rare, but can almost be seen as centralized). In the end, it's not just the device but also the right pipe selection and design. Comparable to underfloor heating.

In the end, it is not just the device, but also the correct choice and design of the pipe.

Look - another good tip for the OP to ask about.

Look at that - another good tip for the OP to ask about.

Practical example from myself:
Since I only installed decentralized fans due to the renovation, I of course also had a ventilation concept created. Tailored to a single occupant (my three kids are not always there). This allows my sufficiently installed fans to almost continuously run on basic ventilation = lowest level. Noise is only noticeable when there is absolute silence in the house otherwise. The quiet PC fan is loud enough to drown out the noise of the fan. So for me, practically inaudible decentralized fans. If I had only installed half of the devices, they would always have to run at higher power = louder.

Look at that - another good tip for the OP to ask about.

No, unfortunately it is doubly useless for the OP: secondly, because the salespeople of the house providers are rather not really competent explainers, and firstly because the ventilation systems, as said, are not suitable as a distinguishing criterion to vote a candidate out. The OP will not be spared from first becoming significantly more enlightened potential customers. Even if we phone-a-friend here reached a unanimous result as to which system would be the best, this would not really help to sort the mixed participant field of the comparison in a helpful way.

By the way, it would be nice if the questioners participated in the discussion again. I find the "burn and run" questioners, who disappear shortly after posting their question, just as frustrating as those who whine after two hours "doesn't anyone really have an opinion?"