RJTECH is not really a "no name" brand in the karaoke market. Every store I've been to that stocks karaoke players carries the brand. No idea how good their general DVD players are.

You're right in that DVD players are largely OEM components with different brand names slapped onto them. There are only a few companies that manufacture the transports, and only a handful of companies that make the processing chips. The rest of it is all about specifying the components and manufacturing the players. Keep in mind though that companies like Toshiba, Pioneer, and Panasonic with their own manufacturing capacity control more of the production themselves, so you get a bit more consistency. With knockoff brands, they get manufactured by a variety of different outsource manufacturers, many of which might not be around a few months from now. (I've read that about 90% of the Chinese DVD player fabricators that were in operation two years ago have since gone bankrupt)

Also, an advantage of buying a name brand is that it's more likely to have been tested for performance and you can gather more information by reading reviews. That way, you know more about how well the player reads different disc formats, and if it has specific issues like audio sync problems, trouble with seamless branching DVDs, and if it has the chroma upsampling error.

IMO, the main difference between no name brands and more well known brands is the customer support. Apex Digital sold millions of cheap DVD players, and had fewer than 20 people handling customer support. But, with even well established companies like Toshiba and Panasonic selling basic DVD players for less than $80, that might not really matter much. If it breaks, you just buy another one.