Okey, I very liked the demostration and the documentation files, so I bought it. First of all, it is a good tool indeed. It has some issues with the work comfort, but it is still better as other tools and programs for this type of models.
It works on Unity 2020.2.3f1, but shows that 3 used methods are obsolete, but it works.
The main problem for me was the terrible lag when the MeshEdit window is open. It is a huge issue for people working on high hz displays. I solved some of the lag by removing "Repaint"ing window on Update...(why repaint every frame btw?) it still display everything normaly and it is just faster now. It can repaint when deselecting object or something like that, but not always.
The design of the window is OK, it is just simple and easy to read.
I am happy with the purchase, but for the price I would expect something that I do not need to correct before use.