Pretty interesting to note that, thus far, Old and New have each won 6 battles.
New wins with - Wyches, Vehicles, Beastmasters, Haemonculi, Incubi, and the Talos
Old wins with Archons, Archits, Reaver Jetbikes, Mandrakes, Decapitator, and Warriors.
Fascinatingly enough, thus far the trend is that New wins the close combat battles and Old wins the shooting battles which is about the opposite of my original thoughts (though, I'll admit, I still think it's lolsilly that Old Wyches lost, I have no idea how that happened)
In any case, next up we'll be seeing ol' Vect himself take the field. What shall triumph, a massively expensive Raider with a huge pile of assault doom in it, or the oddest Walker unit in the game? Only time will tell.