Not sure what you want on this "Battle Card" but the Gartner Magic Quadrant report and the Gartner SIEM Critical Capabilities reports should give you a good view of both vendors abilities and short comings.
Did you find or create a Battle Card? I'm interested in this kind of comparison as well.
I think that this would be helpful for someone looking to purchase / implement a SIEM. AlienVault markets their product as a swiss army knife with everything a security analyst would need. What does McAfee ESM cover?
Anyone in Sales or Marketing listening?