It combines the best of a Centaur and a Lymean, and is everything you want out of a Magic Deer. Compared to a normal Unicorn, it fights better but performs worse as support since it doesn't have as wide a range of skills.
Of interest is their unique fixed skill, TeleportCharge, which is actually worse than Teleport or Charge. It limits Teleport to a straight line like Charge, but without the shield bonus and without attacking. It's only really useful if you want to get to the other side of some difficult terrain or a bunch of units.