Yes, I also consider the cult being more durable than the empire. Their units in general seem extremely cost efficient.
But there were two points that had massive influence on our last match and that simply were completely unfun to play against.
First was, that you can't really defend against the portals mechanic as they can be moved and a new portal can easily be created via stratagem. Put a new portal on the table in a sweet spot and send a rhino with its pulse through. You can't defend against that move and will suffer a huge amount of autohits you can't defend against either. Similar with exploding breachling, no defence possible. You could even chain activate two breachlings or rhinos to do even more damage. Just imagine a 12 inch diameter template autohitting with str 3 or 5 two times. And you can just watch and let it happen.
Another thing we are concerned about is the chaos fissures strategem. We tried it recently at a dual commander game and it was a complete game changer. At the beginning of the turn it was a bit tricky for my opponent, because he had no hand to defend with and suffered some damage. But then the strategems card draw mechanics began to work and things became terrible, since as soon as he had some hand cards, he could also cheat from his hand to get the high cards he fliped before, while still winning the duels. I. E. he cheated a 9 from his hand and won the duel. Because he flipped the red Joker before cheating, he was allowed to put the red Joker in his hand. At the end of the chaos fissures turn, he had 6 handcards between 11 and 13. That strategem appears to be not that good on the paper, but actually give it a try.