Here's the IP addresses and Sender Score ranking for the last three mailings I've received from each of them. The Sender Score number was noted at the time I originally received the message.
A higher Sender Score number is usually considered better. Looks like very generally speaking, Obama's sending reputation may be a bit higher than McCain's. Of particular concern to me is both candidates seem to be mailing from multiple IP addresses. Why is that? I hope it's not to avoid blocking.