The following pic is of the KMC510HX, the KMC415, and the Wippermann 1G8. The pic is a little misleading, because the 415's pin width is actually about .025 wider than the 1G8 on average, which means it will fit even less drive trains that the 1G8.
In this next pic, you can see where the 415's rollers are recessed further between the side plates, making the rollers ride almost at the tip of a 9t driver, which is no good, unless you enjoy replacing drivers fairly often due to broken teeth.
Here is a side shot of the three together. You can plainly see how much wider the 415's plates are at the plate/pin interface. It almost makes the 1G8 look like a normal chain.
From experience, I know that the 1G8 will not fit 9 or 10t drivers with squared tips, like the Ratchet drivers. The rollers are slightly larger so they won't clear the square edges to mesh. I modded a 10t driver to run one on my 20".
I installed, or attempted to install the 415 on my current bike, but only the tips of the teeth contacted the rollers due to the size of the side plates.
This is going to be a compilation thread, so anyone with real experience can add. It may be edited to keep it on subject though.
Refs: Tito24, RiverSideRider, Stussy, Nettyspaghetti, Daniel24, Freddydapice, BrokenBMX, SuperstarDK, HardBMX_Tim. There's more, but I'm too lazy to look them up, haha.