I was wondering, based on your experience, which Mac OS X is the most stable and is the best one to use today?
I’ve been on High Sierra and have had no issues I can think of. El Capitan also was very stable to me and still is modern enough to be able to mostly use.
High Sierra and El Capitan are both good contenders.
I have a 2007 iMac running El Capitan which is extremely stable – but it’s also not doing a whole lot.
My Mac mini server runs High Sierra and is also very stable in most usage.
I’d vote for High Sierra as well.