Well, if someone is sending a cartridge for retipping, it's usually because it's sounding pretty ratty. So it makes sense that the one that comes back is an improvement over what they remember. But the deterioration of a phono cartridge is so gradual, I'm not sure anyone could accurately remember the sound of the original. BTW, I had Soundsmith retip a Transfiguration cartridge for me and it sounded great, so I wouldn't hesitate. It only cost $500 as opposed to a new one for a couple grand, so there's that as well.
Re-tipped phono cartridges
I noticed a lot of ads for re-tipped phono cartridges are suggesting this is an improvement over the original. I respectfully disagree. Regardless of the new stylus the integrity of the original design has been compromised. Think of it as a fine Italian automobile with a blown engine. It can be fixed but is it ever truly the same?