Advantage 1. Not proprietary, when Excel changes to version blah blah, you don't have to change the spreadsheet.
Advantage 2. You don't need Excel to run it, so it is platform agnostic, all you need is a java capable browser
Advantage 3. XML Army data lists use an open source and standards based system
I happen to be sitting in an office with about 5 under-employed crash hot java developers, if you run into dramas, drop me a line? I can be reached at dougmelville on my hotmail address - i am sure you can figure it out from that.
cheers