About 15 years ago, I've been installing SUSE Linux on a PPC 9500. After a while I reverted back to Mac OS 9.1. With recent Mac models I'm running various Linux systems inside a Virtual Box and can't report on how good they'll run natively. Most critical are probably adequate support of power management, HI-DPI Retina resolution and drivers for the I/O ports (Thunderbolt to Ethernet, etc.) without flaws.
If you want some Linux running natively on your Mac any Live CD of a Linux distro should give you a taste of what you can expect. Maybe you even like continuing to have macOS installed as your primary OS on your internal drive and just occasionally boot up Linux from a live USB flash drive. If that's not an option, why not consider Dual Boot (
rEFInd)?
After some long research a year back, IMHO there is currently no desktop Linux that would really make sense to run natively, if one can run macOS. There might be some good reasons for running a Linux server box with no GUI at all, especially to utilise some older Mac hardware for server tasks, but why not run FreeBSD then?
However, if you ask yourself, what Live-CD to try:
1.) Close to the look of macOS comes
Mageia or
elementary OS.
2.)
Debian is used by plenty of institutes and governments and is quite stable.
3.) The Debian derivate
Kali Linux comes with Wireshark out of the box.
Of course it depends on your needs which distro fits you best and maybe Open SUSE, Ubuntu, Cent OS or one of the
many other Linux systems is going to better suit you or could work better on your hardware natively. If you want to learn everything about Linux, then
Linux From Scratch is your route to go.
To get a live CD installed on an USB flash drive there are various helper tools like
UNetbootin or
Mac Linux USB Loader available.