Here's a brain dump for @displayname Regarding inner groove distortion, generally more advanced stylus profiles (Microline, Shibata, Gyger) give better performance because they more closely replicate the cutting stylus when the laquer is made. If you get lucky (and in my experience you usually will) the more advanced stylus will ride in a different place in the groove- a fresh unworn place- so you will get better sound. But if you aren't lucky, it'll ride in the worn area and it'll most likely sound worse.
Some people prefer to use inexpensive conical styli to play worn records and an advanced stylus for nice records. Conical styli tend to be larger though, and this presents a problem. As the stylus travels towards the label, the grooves get tighter and the groove velocity increases. The conical stylus riding in a tight groove results in something called "groove pinch". Think of trying to put 6 pounds of sugar in a 5 pound bag. It won't work. This is why (for the most part- the classic Denon DL-103 and 103R cartridges being obvious exceptions) conical styli are on bottom of the barrel cartridges.
The cartridge type makes a difference too. The stylus moves the cantilever which in turn creates voltage inside the cartridge body- a generator. The lower the moving mass of the generator, the less the cantilever has to work. While your stylus and cantilever are sending vibrations up to the generator in the cartridge, micro vibrations are also being sent from the cartridge back down the cantilever towards the stylus. Obviously this isn't desirable, but it's the way it is.
If you can reduce the moving mass of the generator, you'll reduce unwanted vibration. Moving magnet cartridges have the highest moving mass. Moving coil cartridges are next, and the lowest moving mass are moving iron designs. Moving iron designs are cool because the cantilever doesn't move anything inside the cartridge- the coils are fixed. A tiny bit of iron is affixed to the opposite end of the cantilever from the stylus and is precisely located in the center of four fixed coils. As the iron moves from the groove vibrations, it changes its location between the coils. It's not trying to track the groove and also move a magnet or a coil. The only moving mass is the cantilever itself. You'll get a more precise rendering of what's in the groove with a moving iron design, in my opinion.
Oddly enough, Joe Grado invented the moving coil cartridge. Grados however are moving iron, as are Nagaoka, Soundsmith (which they call fixed coil- same thing) and Goldring.
