That's not really how the comments on alternativeto work. They are relative.

If you got to spotifys page, it will list similar services, each with their own comments, and the comments under youtube music, for example, will be about how it compares to spotify.

So, to leave useful comments, you only have to know how a given piece of software compares to what you used before. You don't comment on how a given thing compares to everything else, only to one thing at a time.

Then, as other people browse the alternatives, they can use those individual comparisons to navigate their way to what they need. Stuff like "this can't replace that for this use-case, because reason, but it does this other stuff" is extremely useful when looking for something that does what you're looking for.