I got my Pocket Dock in. It is larger than the Sik Din. I have a Contour Showcase and the Sik fits through the dock hole in the case, no problem. The Pocket Dock doesn't. It says it will on their website, and you can force the case closed with the Pocket Dock connected, but doing so creates some bowing in the case. As for sound differences, I would give a cautious nod to the Pocket Dock, but the difference is very subtle. Also, as mentioned earlier, the Pocket Dock does not have a locking connector like the one on the Sik. When you start adding some weight by attaching a Y-Cable and a Firewire Power Cable, it wants to slip out of the iPod and becomes a major pain in the butt. If you already own a Sik, I would not recommend getting the Pocket Dock. The extremely small difference in sound quality just doesn't make up for all the inconveniences it adds.