Pros: It's fairly easy to setup and use and takes pretty decent quality captures. I hooked it up to my wii and I was able to play the wii on my laptop without any lag whatsoever. The sound was good and came out clear. The actual casing of the easycap feels like really good quality plastic.
Used the software that came with it which was ulead video studio ce 10 while you may want to go another route for merely watching video or playing a game on the wii for recording it's quite easy and makes it into mpeg2 format.
I have vista and it worked without a hitch for me and after trying a couple of tuner throughout the years for usually more expensive it's nice to have one that works.

Cons: The ulead software that came with it is decent for recording however for watching without recording you should try out some others, media player classic works pretty well. Could never get sound from preview with ulead either.
As for the actual device I can't see any.

Other Thoughts: http://www.youtube.com/watch?v=Vr_y6BtPBTg
Here is a test capture that I did, just captured directly with default settings at 352x240 with ulead.

Bottomline: Really good price, I have seen worse devices for much more than what's here. It's a no brainer type thing which is good when you want to easily convert old home movies etc.

Pros: * Cheap!
* No external power needed
* Small and convenient form factor
* Easy to get it running

Cons: * My unit seems to have some kind of (hardware-related?) problem where the sounds starts to hiss/crackle after a while when recording.
It should be possible to overcome this by using line-in to record audio instead of the audio input on the device, since video works fine all the time.

Other Thoughts: It's nice that a USB-extension cable is included. The included software also does it's job, although there are better options available online.

Bottomline: Amazing that you can get a capture device for such a low price!

Pros: - Small size.
- No external powersource, completely USB powered.
- Supports both NTSC and PAL.
- Have audio inputs in case you don't want or can use the line in on your soundcard.
- Unbeatable price. Have seen the same product for 3x the price.

Cons: - If used in with the higher resolutions the deinterlacing isn't that great but I'm not sure if it's the software I am using (not the bundled one) or if it is a hardware issue.

Other Thoughts: Seems to be the same product as http://www.dealextreme.com/details.dx/sku.5707
Keep in mind that if you use the audio inputs it will not output that sound directly to your speakers like it might do if you use your soundcards. That's fine for capturing but if you intend to use it to be able to watch stuff on your computer screen then line in on the soundcard is they way to go. (This is why it didn't get a 5 in Ease-of-use).

Bottomline: I bought this to be able to connect composite equipment to my laptop and for my needs it is perfect and I can't complain about the price.
I have not tried the S-Video input yet.