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.
