Hippeis are a mix of good old fashioned Greek know-how with the practical needs for an effective medium cavalry force.

Hardy
Can Form Wedgen

Greek cavalry is not the most awe inspiring and powerful in the world, but they are no slouches either. Hippeis are a mix of good old fashioned Greek know-how with the practical needs for an effective medium cavalry force. The result is the wedding of linen armor, attic helmets, and hoplon shields to cavalry spears and the xiphos, which produces a warrior with excellent all-round equipment. Since they are mainly drawn from elite nobility, these cavalrymen have a high morale and a good discipline. They ride stout horses whose stock was imported from the north. They are an able, if not spectacular, medium cavalry.

Historically, Greek cavalry was always thought of as better than Roman cavalry, even though it was not particularly significant. The Greeks have enough trouble keeping the equestrian minded Macedonians to the north at bay without having to worry about doing much of significant note.