The reviews seem more positive and people can get it to work easier. Looks like it's a repackages EasyCap with some firmware changes.
There's also this:
http://www.amazon.com/Diamond-Camcorders-supporting-composite-connection/dp/B000VM60I8/ref=pd_cp_e_2
Which has significantly more positive reviews and supports 720x480 resolution. I'd probably read up a bit more on that and purchase it if it's good for what you need. The price is higher but the video quality will look better.
I looked up some Diamond VC500 quality tests on YouTube and they seem much better than EasyCap recordings, and most of the videos weren't even rendered properly (black bars, resampling enabled). So yeah, I'd go with the Diamond VC500 for sure.