People like to shit on MS, but Microsoft's commitment to backwards compatibility allows you to keep the same OS and use your PC to use all the software you paid for, for FAR longer than any Apple or Linux PC.
- Automatically upgrading devices to Win10
- Announce that they will keep adding upgrades to win10 instead of creating new releases
- Office 365
- Require win10 to develop for windows phone 10
and important software companies like adobe/autodesk moving to subscription model isn't gonna help.
And once you have the hardware new enough to run hardware virtualization well, there are truly no limits other than raw RAM and CPU.
I've revive an iMac 5,1 under Debian, and it runs. But with 1 GB RAM, it's good for only a small handful of Web browser pages before starting to swap heavily. The system should be good for memory and HD upgrade, though I've yet to look into that.
Compared to a newer Retina iMac, it's actually the screen which is one of the elements that's got me hesitating on an update. The resolution (and brightness) are sufficiently poor that even an update wouldn't give it all that much utility. Given the cost of modest new generic PC hardware, I've got to question the validity of that.
For non-Web use, basic apps, shell, and server roles, it's just fine. It's browsers that are absolute resource monsters.