Arch which aims to take the latest cut of everything. If you have time to keep your desktop updated and need that extra 1fps in a game, its a great choice.
Debian aims for stability, this means your drivers and text editor might be .. 2 years old! But if it works on install it will stay working
Red Hat Enterprise Linux aims for stability but will try to backport drivers. I honestly believe its packaged to always pull in gtk. It aims to provide tools to encourage people into support contracts.
Almost everything else is downstream of those with a twist. For example
Ubuntu is downstream Debian with 6 month release schedule, non-free enabled by default and other deviations to encourage people into support contracts.
Mint is downstream Ubuntu with the deviations removed.
Stuff that isn't downstream tends to have a highly specific purpose. Fedora started life as upstream RHEL, now it seems to be Red Hat's research plaything (e.g. immutable sounds cool, lets try it in Fedora).
My advice is go to one of the big 3, try them and only bother with one of the million down stream distributions if there is a Unique Selling Point for something you actually care about.