I run the quietest fans I can find at reasonable prices in everything, so Arctic F12 mostly. Those San Ace look neat but 50dB is just way too loud for my setup!
homelab
Arctic F12 are quite cheap, I see no reason to buy used fans tbh. After many hours every fan will become noisy or die, but if your fans look good I wouldnt worry too much. I had 8 F12 running at max speed for 2-3 years and other than dust there was no sign of wear, but they are dirty af
I'm a big fan of 120mm for the airflow to noise ratio. They tend to last. You figure they're doing less revolutions over their life than a high rpm smaller fan.
I used to overclock back in the day when that was still a thing (2004-ish) and 120mm fans were amazing with a speed controller, have them slow when using computer normally, and speed 'em up when playing a game.
oh overclocking is still a thing, I do that on my desktop, fan curves can be handled in the bios/uefi. I like good quality higher rpm fans for even desktop use because even at lower speeds they still push a ton of air and are a lot quieter than the cheaper fans on the market. still not absolutely silent, but they don't bother me. That's what headphones are for haha