Detail is how well you can pick out individual voices and instruments and how much of their timbre you can appreciate. Percussion cannot be used to determine detail as it is hyper-detailed and leads to a false sense of detail. The best test is a symphony orchestra.
IMHE many people prefer systems that are on the bright side. This gives a false sense of detail. It also increases sibilance and makes cymbals sound tinny.
How a system is performing requires either measurement or comparison with a known flat source such as headphones. I prefer measurement. IMHO every audiophile should have a USB measurement microphone.
If you want to hear a wonderfully detailed system look for ESLs driven by a powerful class A amplifier.