You might want to try posting to the MP3 Insider forum or e-mail the hosts at firstname.lastname@example.org as to why they don't review the units you are asking about. That forum doesn't get as much traffic but sometimes one of the hosts (usually Jasmine, but she'll be on vacation this coming week) replies. I listen to this podcast regularly and I seem to remember that they don't have a very high regard for these players (not specifically by name but as a class of players that Chinese manufacturers generically call mp4 or mp5 players).
I do recall hearing that a lot of these are sold in South America, namely Argentina and Brazil. But that could have been one of those spam posts that were deleted.
Like I said before, the only one I've seen up close and personal was the Onda iPod Touch wannabe. Definitely was not impressed by its cheap plastic feel. And just because something is plastic, it doesn't have to feel cheap. But that Onda felt cheap. If that was representative of all of their products, I would definitely stay away from them.