The biggest advantage I can see is that it will have XOS 2.X installed on it giving it out-of-the-box FTP for setup. This feature in itself is a big help to installers and noobs. No more burning CD-RW/DVD+RW.
If you buy a pre-ICE then you must burn a CD/DVD to do anything.
During my very first install of a Xenium I had to do so much reading on the burning of CD/DVD media just to get started. I tried numerous burning methods, media, XISO, gdfimage, Quix image, UDF. It was a nightmare. Sure I have it all figured out on my end now.
Sure you may get lucky to find a distributer that will pre-install XOS 2.X for you, but with the ICE version youre sure to know it has 2.X on it already.