I have no experience with the $40 box, but can recommend
this $150 one. Output resolution is selectable between 640x480, 800x600, and 1024x768, at either 60Hz or 75Hz. Input is composite or S-video, with a pass-through and window-over VGA input. Quality is excellent on my 80" LCD projection! Note that progressive inputs aren't supported except as VGA-in, but it auto-selects 3:2 or 2:2 pulldown to do de-interlacing.
I bought one because my hot deal antique LCD projector did terrible color rendition on its S-video or composite inputs. This unit is near-dead-on (per Video Essentials) right out of the box!
Direct from the mfg is the best deal I found on these - some eBay folks try and sell them as $199 retail items.... You pretty much have to call the company to check order status as they take online orders fine, but have never responded to my e-mails. I always get a person on the phone and he answered all my questions instantly - including getting me tracking #s.
HTH,
Richard