Super+: Brand- or Cheap-Sprit ?

No, no, not again this discussion about Super and Super+, this time it’s not about the variety, but about the brand. Based on some engine damage, which is related to Super ohne+, you have already persuaded me to refuel Super+. Ok, so far I have mostly filled with Aral, if no Aral at hand, then “exceptionally” with other, but always big brands, BP, DEA, Shell, Esso. To save a few cents, I would like to know how it is qualitatively with others like Jet, Agip, OMV, etc. or even crazier with the supermarket filling stations at Metro, market purchase, Kaufland. etc… Is only the octane number relevant or also the aditives that each big manufacturer so mixes? What have you done for experience?