Apparently the quality of the temperature control also matters quite a bit. It seems the TS100 has little problem in either of those departments https://www.youtube.com/watch?v=HgrB5P-rDLw https://hackaday.com/2017/07/24/review-ts100-soldering-iron/ , especially if you use a 24V power supply. It's also embarrassingly cheap compared to the mid-spec soldering irons from prestige brands which it tends to match.