I purchased witch several years ago, and my main complaint is that it takes a long time to show all my windows if there's a lot of applications windows, and this did not use to be the case. It's fine if I'm switching between windows in one application, but if I say, want to show all the windows open on my computer, it takes 3+ seconds to display the interface.
I discussed it with the Many tricks support, and apparently it's a problem with MacOS