>If, hypothetically, you had a system that was sending/receiving data in the form of ADO Recordsets, would there be any reason, other than to keep up with the times, to start flinging XML data around instead?

Yes, platform interopoability. Or however its spelled. Non-Windows platforms don't support COM, thus ADO isn't an option. But if you gave a Linux box some XML, it would be able to play in the same sandbox.

If thats not an issue, ADO will work, and it will be more effecient (usually).