Tjyven My RPM is generally Max at 1200 rpm for espresso and around 200-400 for filter.
Depending on coffee the Max RPM tends to blend the flavours, decreasing alot of harshness for coffee which are of lesser quality or roast. Recently i had a Tim Wendelboe espresso roast which tasted very muted at higher RPM, lowering the RPM brought out the acidity and characteristic of the coffee.