I love mine, it has a fresh battery OEM battery as well. Runs the latest OS with OpenCore Legacy. But it's starting to get a bit annoying. Usable, but it is starting to feel slowish, the fan kicks up frequently.
I might still keep it another year or so, which is a testament to how good it is and how relative little progress has happened in almost 10 years.
If I still had my 2015 I would have applied some liquid metal TIM by now, I did a paste refresh and that worked very well to get the fan under control.
Did you disassemble the fan assembly? And applied new thermal paste?
I'm not using mine any more, but I noticed a big difference when I replaced the battery and got all the dust out this spring. Also installed a new battery. Still quite a hard sell on the used market :)
If it's got a full function row, it will probably work just fine under Linux. My 2014 MBP chugged pretty hard with OpenCore but handles modern Linux distros much better.
I might still keep it another year or so, which is a testament to how good it is and how relative little progress has happened in almost 10 years.