Most important in a case

[jdaggon]

Most important is that it has plenty of rom for expansion for both drives and expansion cards

 

[Icaraeus]

Absolutely not.

Most important is airflow. Airflow comes first. Next comes form factor, and then noise levels. *Then* it's down to expansion.

 

[CountMike]

I would put form factor first, it could be best ventilated or expandable and still not fit MB in it. Personally, I have to pay attention to number of drive bays because of 6 drive removable bays but large cases like that are also good at cooling.
BTW, it's this one: https://www.ebay-kleinanzeigen.de/s-anzeige/chieftec-dragon-pc-gehaeuse-server-atx-big-tower-mit-netzteil/853939149-225-3423