Using RON95 for my Proton FLX 15mth old (13k KM). Enging sound is getting louder. Even can hear it from 10 car away these day.
For slow driver just want to move from 1 place to another place, RON95 is good enough.
For driver dont want to spent more time on the road or efficiency drive. RON97.
Quality is different. RON95 need to step harder on fuel paddle which in return will stress you engine which causing the loud engine sound.
Lots of my friend using RON95 but friendly speaking, they prefer RON97 but due to the COST, no choice.