USB vs dock for iPod on Peachtree units?


I am looking at the Peachtree Audio Decco 2 vs iDecco. The main difference I see in the specs is the iDecco has an iPod dock and also USB connection capability for an iPod, whereas the Decco 2 has only the USB capability for iPods.

What is the difference between these connections in terms of passing the iPod output through the DAC/Preamp stages and the resulting sound quality?
jimthewebguy
I got the very first Japanese iDecco sold in Japan!

Just as an update to end this thread, people at Peachtree as well as on this side convinced me that the Japanese version is better for the power system here. I got the first unit from the distributor, before it hit the market here. I ran into a couple of questions while setting-up, which I'll ask in the tech forums if I need to. Again, thanks for your help with my selection.
Just purchased an iDecco and it is FABULOUS....with the right speakers it's just terrific. Couldn't be happier.