Alt tab is okay but it has performance issues (sometimes window switching is instant, sometimes there's a slight but perceptible delay). The devs have acknowledged it and said that it cannot be fixed.

Other pet peeves include the smallest window thumbnails are enormous and enabling mouse hover to switch windows causes me to switch to the wrong window, and thumbnails are often stale.

I think MacOS would be much more unusable without alt-tab, like this app is a critical piece of software that has to be installed on any MacOS machine I'm using. But it does sometimes miss a window, like it doesn't show up in the window list in alt-tab even though it is open. And then I have to use the three finger swipe up thing to find it. Not a huge deal but occasionally annoying, and I assume it is because they are limited in the access they have to this information, which Apple could make available if they wanted, but have decided not to.