I tried using mklinux on a PPC (a Performa, maybe?). I don't think X worked at the time, so it was strictly text mode. "Text mode" I should say: there was no 80x24 text mode so it was eg, a 640x480 bitmap using pixels to render the characters to draw the console. Which looks nicer and is more flexible but much slower.
I once tried Linux on an old G4 MacBook (Power Chip - before the Intel chips).<p>It was just as slow using Linux as it was using 'Tiger', and also some peripherals weren't supported.<p>For what it's worth, Linus used to use a MacBook with Linux. But that was several years ago. I don't know what he uses now.
I used rEFInd to install it on my Mid 2015 MacBook pro last year. It works great. I heard theres some custom configuration needed for the touchbar in the newer ones though.
what are your concerns?<p>linux runs fine on a mac. given the limited selection of hardware variations, it is less likely to run into surprises. as far as i could tell all peripherals on my mac are working. the boot manager refind also works well.<p>the only thing you need to do after installation is to configure the touchpad to support 3 mouse buttons. once that's done, linux on a mac is a great experience.