Sure they are! FM bodyguard is simply awesome ... I had a couple of em (50 cataphracts each) butchering 1000 men in a city assault (well, they were levies without a leader and so on, but still 1000 vs 100!).

I never meet'em in my other games (as Romani, I usually conquer all the west, then push eastward but get bored by endless ptolemis stacks there's no way to stop) ... and I think I would have regret it (as in real history ...)