Okay, I received the EasyCap yesterday, so I will write my review now.
Honestly, I don't really know if it's worth it. to test it I played Modern Warfare 2. While the device description says it can handle up to 720p at 30fps, I could only set the Xbox to 420p. I simply can't play on 420p when the Xbox is plugged in directly to my monitor, but this seems to add some compression to make it even worse. It's unplayable, but my brother said it's not unwatchable. It seems like a lot of the people on Justin.tv and ustream.tv have about the same quality. Oh one thing about the EasyCap software, it doesn't support the audio, so you will have to get an RCA to 3.5mm adapter if you want audio. Another thing about the device is it seems just a little bit slow. So you walk into a room, try to shoot someone in there, but in realtime you're dead before you ever saw him. Now it's not really this bad, but in those split second reactions, it does help to be live.
As far as recording movies goes, well it doesn't. The recording feature that is on the EasyCap software will let you choose where to save the recording to, the quality of the recording, and if you want it to record to the RAM. Recording to the RAM limits the file size to 2GB, but will start making your computer unresponsive at about 75% of your RAM capacity. It does make the video a little smoother, but it's still not great. Whenever you record, it records at 30fps, but it drops one second's frames every few seconds (depending on the quality you have set and if you are recording to RAM).
So here are some screenshots I took for you to decide. They are completely unaltered, except for two which have been cropped to keep under 3MB. I would recommend you download these and view them at full resolution. If you want any more let me know.
This is the window on my desktop at "Actual resolution". You can resize it to half, actual, double, and full screen. I am shooting in this one.
Same thing except I am spinning to show off the lines that appear on horizontal movement. EasyCap has an option to turn of and off V-Sync, but that doesn't seem to change anything.
Here is a screenshot of the window only.
That same screen in fullscreen view. Note if you resize it to 720x480 it actually doesn't look as bad as the above one, or I don't think.
Plugged it into my VCR (I know I know.) and thought it wasn't as bad for watching something.
And fullscreen.
Hope that helped!