[HotNifeThruButr]

I once took down a Personal Luck'ed, Ethereal (forgot how he got it) Sphinx inside a castle. I ended up losing about 2/3 of my forces, but since tower fire can berserk some einheres, they didn't route when everyone else did. They were so tired they ended up attacking once every two turns.

So, to recap, dual weapon soldiers are good if you have no alternatives. I'm talking Falchioneers, Einheres, and Centaur cataphracts, to a lesser extent. When it's inside a fort of some sort, berserkers are almost essential.