I will say, just for the heck of it, I tried a Thunder Lizard army composed of:
1 Oldblood Carno (general)
1 Oldblood Carno
1 Scar-vet Carno
6 x Stegadons
1 Hunters of Huanchi (bolas).
I played against my buddy's Soulblight Gravelords. Now, he wasn't running his most hammer units, but it was still a tough battle which came down to the final round. I won by 1 point thanks to a silly luck roll.
He had taken the tactic Magical Mayhem (kill a unit with magic). I unbound his Vile Transference with Heroic Willpower and he failed Blizzard (we had no bonus dice). He did cast Arcane Bolt with his on-foot Vampire Lord and was holding it to blast my very hurt Stegadon after combat. However, I had a Carno within 3" of the Vampire Lord. So, just for fun, I attempted the Carno's "eat a model" monstrous action and rolled a "6!" The Vampire Lord only has 5 Wounds. Chomp! Goodbye Vampire Lord and goodbye Arcane Bolt.
Thunder Lizard makes it fun to field all monsters, but it's normally not practical. I know the Stegadon and Carnos are pretty cheap now, but it's easy to whiff with them (at least for me). When our monsters do whiff their combat phase you REALLY feel it. I think the Stegadon's bonus monstrous action should be changed to something you can do every round, not just on a charge. I wish that one of our Carnos had a 3+ save. But, we do have Bastiladons with 2+ saves, so I can't complain too much.