Even if it feels like sculpting with foam, Medium is a pretty revolutionary sculpting program. The problem is that it has to unwrap the textures automatically, and it does that by creating 30 or so individual “islands”. All those individual patches of texture needs to be aligned perfectly. If you started animating the model, those patches would likely mess up even more.
The chinks on the edge of the box shape is caused by Medium creating the box out of lotsa triangles. Medium is really bad at exporting hard shapes. Natural soft shapes do much better.
Personally, I still consider using Medium for the raw sculpting, simply because it is way fun! But I will clean its retropology in Blender, and also colorize it there, and generate new normal maps.
