IMHO, the bigger difference is if they are dual or single
coils.
A dual coil is more likely to burn the wick (polyfill) if it is not full of e-liquid, because the wick around the upper coil will have a tendency to burn as the juice level falls in the carto.
If using dual cartos solo, this will require more frequent "topping off" with juice to prevent this from occuring.
If using them in a tank, the upper coil lies above the wick hole supplying juice to the carto. After some time
vaping in a cartotank, I've found dual coil cartos will begin to taste burnt. I rarely get this issue with single coil cartos used in a tank.
Other than that, XL cartos just hold a larger capacity than standard length.