In personal experience, all of these have held true. Mise is just easier to use than asdf and I don't have to `asdf -h` every time I have to use it. The performance is significantly better and I can use mise exec in shebangs without sacrificing too much startup time. And it's easier to install because it's a SLSE. I wouldn't say it's worth deliberately switching from asdf (though I would, because asdf's CLI is an endless annoyance to me), but if you're on a new machine I don't think there is a reason to use asdf over mise.
Either way, I don't think many people are checking in tool-versions files. Most JS templates specify a range of node versions they work on and leave it to you to specify which one. I don't think this is unusual for most other languages I use, like ruby.