'Crons just got a new book, and they are
pretty tough to kill. Some of their old weaknesses (like being swept in melee) went away too. The good news is, unless your buddy plans to spend hundreds of dollars on flyers, he'll probably be relatively slow moving.
Whatever army you go with, you'll want to focus fire. If you let his units live, he'll reinforce them with fresh bodies. He'll also have tons of units with a special rule that makes them AV 13 until you inflict a penetrating hit, so you'll want to make sure you have at least a few high-strength weapons running around.
'Crons are super durable, but they don't have an abundance of overwhelmingly strong powerful weapons. They have good weapons, don't get me wrong, but nothing you can't deal with. Just keep hitting each machine until it drops.