I have an old Mac Pro that has been collecting dust for years. Today I bought an SSD and install Debian on the machine. It works flawlessly.
Further reading revealed that there is an active community around the classic mac pros and thanks to their modular nature they can be fully upgraded. People even upgrade the CPUs in this thing.
So if you like playing around with a PC like the old days, that is also Linux compatible, a Mac Pro 5,1 seems a good choice. AFAIK you can get it for cheap and a decent upgrade won't break the bank.
I love the old Mac Pros and even built a trashcan setup for Debian a few years ago. But TBH, they use a lot of electricity for the processing power they provide. If you already have one or can get one for free, great, use it. Linux runs great. But I wouldn't go to OWC and buy something that would be outperformed by a fanless, low TDP machine these days.
Depending which version of the MacPro you have exactly, that machine from 2010 is around the speed, or slightly faster, than a Raspberry Pi 5 with 8 GBs of RAM these days. The problem is the energy consumption, not really a green machine to run.
Oh man, I gotta dust off my wife's old 2009(?) MacBook now. I think the battery might be toast, but hopefully there's enough of a cult following that I can find a replacement for that as well.
As for Windows, I don't know of any methods to get Windows running outside of macOS, but many people utilize Parallels for Windows apps or the desktop experience.
My dad has one from 2008 or 2009 with a swapped motherboard and firmware mod to 5,1 so he can run more recent mac versions. Also put in a r9 280 with custom firmware but somehow is still using all spinning hard drives
I don't believe it works "flawlessly" and I'm tired of people exaggerating their experience in such a misleading way. There's always some hitches and I don't get why people basically have to cake their OS experience with makeup like this.
Because you're making stuff up. Literally every install of an OS has some little issue here and there-- but this is my mistake for assuming any Linux community could be humble enough to cut the BS and stop acting like Linux is a flawless experience. I'm out, keep hanging out at that ~5% market cap and wondering why folks don't flock over despite it being free.