Just wanted to second the above statement: this product DOES preserve stereo separation.
As of today, August 21, 2012, the white Belkin splitter preserves stereo perfectly, with minimal loss in volume. Not sure what happened on so many of the other orders, but stereo is definitely working with the product I have in hand.
For those of you who aren't sure what panning/stereo sound means, an easy example is the song "Such Great Heights" by the Postal Service. The opening 30 seconds have an extreme example of stereo sound. The short, high-pitched beep sound is being rapidly 'panned' left and right between each beep. [Keep in mind, if you search up a video of "Such Great Heights", you might actually find a mono version. This is one where the sound has been compressed to a single speaker model, so the sound is equally distributed between the two sides. The sound at the beginning is so extreme though, as long as you have headphones on (and probably even without them), it will be obvious if you got a stereo or mono version of the song.]
Some other example songs with heavy use of stereo elements:
- "Strawberry Fields Forever" by The Beatles
- "Purple Rain" by Jimi Hendrix
Anyway, having just tested the Belkin product using these songs, both plugs are definitely preserving stereo.