The Dark Eldar still play to a certain extent like the Eldar. Different in special abilities, but the unit types mostly differ in cosmetics, I feel. Even still, without a good campaign it just doesn't hold up unless you can get it dirt ass cheap. The sisters are a little fun, but only for a couple of bucks.
As for the Tau, I think that the stealthsuit teams work very well, but watch for detectors. Obviously when that becomes a problem, you have to either wittle carefully or switch out your spotters.
The hammerheads are great, but they need to be protected cause they dish it out, but don't take it as well as some vehicles. Of course, adding the Kroot rush on top of that keeps the enemy distracted.
I've never mixed stingwings in the mix, but Kroots, stealthsuits, and a few heavy hitters will make a hole in them, discounting Necrons, which hold the line like no one's business. As for Mont'ka or Kauyon, it depends. I go with Mont'ka, cause I like the Crisis and Hammerhead for turtling and then mobilize when ready to assault. My way of playing though. Keep in mind that the Tau are good at holding their own for a bit and assaulting at the best opportunity. I was playing a friend of mine (he was Ork), and his first wave of max units ran into my line and were torn up, just obliterated. I struck back, but the size of the map allowed him to get back to half capacity and do a lot of damage to me. I lost, but it goes to prove that if I just moved up my defensive line and reset, I would have steadily pushed him back, at least had a chance.
