I bought one. I think it's really neat, although the screen is slightly smaller than the portable Genesis, and it has the same sound issues (pitch is off by about a half step). Other than that, though, I have no real complaints.
I think some people have expectations that are too high for these price points. What can you really expect for $30? It plays most VCS games almost perfectly except for that sound issue that most people don't even notice. Has a rechargeable battery. Backlit screen. I mean, when Ben Heck first made his VCS portable, people were willing to pay almost any amount for it and that thing weighed like 10 pounds! I think the FBP is pretty great all things considered.
I think it's ok to wish for more and then say you're willing to pay for it, but that can be said about almost anything. The trick with any product is to figure out the price point that's going to be the most profitable; not everyone would be willing to pay $80 or $100 for a device like this with more features or better build quality. I'd probably just stick with emulation on a PSP or something if the price was much higher than the $30 I paid.