What I’ve "heard" in comparing tables and arms in my system, using the same cartridge, was artifacts that went missing on the better set up. For example, when I went from a Kuzma Reference and Triplanar to the Kuzma XL and Airline, there was less of a ’halo’ and sense of a turntable spinning as the source of the sound. I didn’t appreciate that artifact was there until it was absent. Does that make sense?
Similarly, when I changed platter weights, from the factory screw down clamp to the Stillpoints some years ago, at first I thought the Stillpoints robbed the bass from the system, but after adjusting the woofers and tweaking the gain, it was pretty obvious that the factory clamp was adding something- a bump in the mid bass that gave the sound a more propulsive aspect; without it, and the Stillpoints in place (after adjusting other things mentioned), the Stillpoints made everything a little more relaxed, less frenetic. I prefer that.
These things weren’t something I had to strain to hear- they were apparent.
The difficulty in my estimation is getting the tables/arms, etc. in one system and being able to compare them directly without other variables.