The 'variations on the theme' observation is an important one. These show up with just about every label on them. While they're all pretty much the same thing made in the same couple of places, some do have slightly different specifications. While I've seen a couple that had slightly better electronics than average, they are always shooting for a price point and a particular market. But I think Jeff is right for the most part.

If you find a decent, playable example and do a simple upgrade that's affordable, these can be OK for someone who doesn't need a lot in a mandolin and there are a lot of those players out there. There's a place for everything. My biggest complaint is that the mandolin part itself tends to be on the very low side and they often don't live very long. Tops collapse, neck joints fail, all that.