I find it quit amusing how the opinions differ and by which considerations and experiences those objectively subjective decisions are drawn.
I for my part have had a rough start with Catalina but ever since the last dot (10.15.5) release I'm mostly satisfied. That said I would argue that Mojave has been a pretty solid release, though purely subjective I find High Sierra one of the most stable ones yet, and I even recommend it for machines that are artificially limited to El Capitan. I read a semi-analytic comparison regarding bugs and overall stability a while back which I cannot find right now, arguing how Snow Leopard was far from being the holy grail OS it's now hailed to be, but rather being the comparatively last solid release till Mavericks. As I've been using macOS since release 9 (and I do not refer to Mavericks), I consider myself relatively unbiased regarding any specific release, though I still have some kind of a nostalgic relation to 10.4. This might stem from Tiger being somewhat groundbreaking regarding underlying software technologies including spotlight and double "emulation" in form of running PPC OS9 applications as well as PPC code on Intel machines, but I admittedly really liked the AQUA UI being at it's peak having the blue menubar apple logo, the sleek blue default background, which still is the default background for the display tab under system information today and, of course the brushed steel window theme.